OUTLINES  OF  ECONOMIC  ZOOLOGY 

REESE 


OUTLINES 

OF 

ECONOMIC  ZOOLOGY 


BY 

ALBERT  M.  REESE,  Ph.  D. 

PROFESSOR  OF  ZOOLOGY  IN  WEST  VIRGINIA  UNIVERSITY 


W11H   194  ILLUSTRATIONS 


PHILADELPHIA 

BLAKISTON'S   SON   &  CO 

1012   WALNUT   STREET 


COPYRIGHT,  1919,  BY  P.  BLAKISTON'S  SON  &  Co. 


THK     M  A.  P  1,  E     PKKSS     YOKK     PA. 


PREFACE 

While  there  are  a  few  so-called  "economic  zoologies"  on  the  market, 
there  is  none  known  to  the  author  that  makes  the  economic  aspect  of  the 
subject  the  main,  point  of  attack,  with  morphology,  habits,  etc., 
secondary.  Hence  this  volume  which  is  based  upon  a  brief  course 
in  economic  zoology  given  by  the  author  for  several  years  in  West 
Virginia  University. 

The  book  may  be  used  in  several  ways.  As  followed  by  the  author, 
the  course  may  be  given  as  a  separate  one  to  students  who  have  already 
had  the  regular  elementary  course  in  general  zoology.  In  this  case 
the  students  will  be  familiar  with  the  classification,  structure  and  habits 
of  most  of  the  type  forms  discussed,  but,  if  desired,  additional  labo- 
ratory work  maybe  arranged  for  the  study  of  certain  parasitic  and  other 
economically  important  forms  not  generally  considered  in  a  general 
laboratory  course.  Or,  the  text  might  be  used  in  a  beginning  course 
in  zoology  by  some  amplification  of  the  morphologic  and  other  aspects 
and  considerable  increase  in  laboratory  work.  Again,  it  could  well 
be  used  as  supplementary  reading  with,  say,  one  hour  credit  per 
semester  for  the  year,  in  connection  with  the  regular  elementary  course 
in  general  zoology. 

It  is  thought  that,  used  in  one  or  other  of  these  ways  or  in  some  still 
different  way,  it  should  be  especially  useful  to  students  in  agriculture, 
who  want  a  "practical"  course. 

Various  sources  of  information  have  been  drawn  upon,  and 
recognized  authorities  in  each  subject  consulted  so  far  as  possible.  The 
publications  of  the  Government,  especially  those  of  the  Department 
of  Agriculture,  have  been  freely  used  and  quoted. 

The  figures  have  been  borrowed  largely,  either  from  technical  or 
from  more  popular  works,  whichever  gave  the  best  ideas  of  the  animals 
portrayed;  the  source  is  indicated  in  every  case. 

The  brief  bibliography  at  the  end  of  the  book  is  merely  to  aid  the 
student,  who  may  have  become  especially  interested  in  some  animal 
or  group,  to  get  more  detailed  information. 

393366 


VI  PREFACE 

The  author  is  much  indebted  to  Mr.  E.  W.  Nelson,  Chief  of  the 
Biological  Survey  of  the  United  States  Department  of  Agriculture, 
and  to  some  of  his  specialists,  for  reading  the  proofs  of  this  book 
and  for  various  changes  suggested. 

ALBERT  M.  REESE. 
WEST  VIRGINIA  UNIVERSITY, 
MORGANTOWN,  W.  V"A. 


CONCERNING  THE  IMPORTANCE  OF 
ECONOMIC  ZOOLOGY 

"In  its  relation  to  public  welfare  economic  zoology  is  of  the  most  vital  and 
far-reaching  importance.  Animal  life,  from  its  lowliest  organisms,  among  which 
lurk  some  of  our  deadliest  foes  as  well  as  beneficent  friends,  to  the  highest  verte- 
brates, touches  and  effects  our  lives  and  welfare  in  innumerable  ways.  It  must 
be  studied  in  all  its  phases  as  never  before  to  guard  against  previously  unsuspected 
or  little  known  diseases  of  man  and  domestic  animals,  as  well  as  to  develop  the 
wealth  and  ever-increasing  variety  of  products  from  which  we  obtain  food,  medicines, 
clothing,  dyes,  ornaments,  and  an  endless  number  of  other  useful  articles.  No  man 
can  now  be  considered  well  informed  who  has  not  a  considerable  knowledge  of 
economic  zoology  in  its  more  direct  relationships  to  human  life,  while  to  the  scientific 
investigator  the  subject  has  the  charm  of  endless  variety  and  service  to  mankind." 

From  an  address  delivered  at  Baltimore  on  December  28,  1918,  by  Mr.  E.  W.  Nelson, 
Chief  of  the  United  States  Biological  Survey. 

"On  the  whole,  I  think  that  there  is  no  branch  or  stem  of  zoology  now  so  im- 
portant to  this  world  as  economic  zoology;  and  in  the  teaching  of  it  the  vast  majority 
of  America's  higher  institutions  of  learning  are  fully  twenty-five  years  behind  the 
times. 

"I  have  made  at  least  six  attempts  to  induce  universities  and  colleges  to  establish 
chairs  of  economic  zoology,  and  have  failed  in  all  save  one." 

From  a  personal  letter  from  Dr.  Wm.  T.  Hornaday,  Director  of  the  New  York 
Zoological  Park,  written  December  30,  1918. 


vn 


CONTENTS 

CHAPTER  I 

PAGE 

PHYLUM  PROTOZOA i 

Class  Rhizopoda i 

Class  Mastigophora 3 

Class  Sporozoa 4 

Class  Infusoria 10 

CHAPTER  II 

PHYLUM  PORIFERA n 

CHAPTER  III 

PHYLUM  CCELENTERATA 15 

Class  Hydrozoa 16 

Class  Scyphozoa 16 

Class  Anthozoa 17 

CHAPTER  IV 

PHYLUM  ECHINODERMATA 20 

Class  Asteroidea 24 

Class  Echinoidea 24 

Class  Holothuroidea ; 24 

Class  Ophiuroidea 25 

Class  Crinoidea 25 

CHAPTER  V 

PHYLUM  PLATYHELMINTHES  :  FLAT-WORMS 26 

Class  Turbellaria 27 

Class  Cestoda 27 

Class  Trematoda 29 

CHAPTER  VI 

PHYLUM  NEMATHELMINTHES  :  ROUND-WORMS 31 

ix 


10  CONTENTS 

CHAPTER  VII 

PAGE 

PHYLUM  ANNULATA , 40 

Class  Chaetopoda 40 

Class  Hirudinea 42 

CHAPTER  VIII 

PHYLUM  MOLLUSCA 44 

Class  Lamellibranchiata 45 

Class  Gastropoda 58 

Class  Cephalopoda 66 

Class  Amphineura 67 

Class  Scaphopoda 67 

1       CHAPTER  IX 

PHYLUM  ARTHROPODA 68 

Class  Crustacea 71 

Class  Onychophora 78 

Class  Myriapoda 78 

Class  Arachnida 79 

Class  Insecta 83 

CHAPTER  X 

PHYLUM  CHORDATA:  SUBPHYLUM  VERTEBRATA 107 

Class  Pisces 107 

CHAPTER  XI 

PHYLUM  CHORDATA:  SUBPHYLUM  VERTEBRATA. 

Class  Amphibia 123 

Order  Apoda 126 

Order  Caudata 126 

Order  Anura. . 126 

CHAPTER  XII 

PHYLUM  CHORDATA:  SUBPHYLUM  VERTEBRATA. 

Class  Reptilia .  . .  135 

Order  Chelonia 136 

Order  Lacertilia 148 

Order  Ophidia .  153 

Order  Crocodilia 170 


CONTENTS  XI 


CHAPTER  XIII 

PAGE 
PHYLUM  CHORDATA:  SUBPHYLUM  VERTEBRATA. 

Class  Aves '....' '. 17? 

CHAPTER  XIV 

PHYLUM  CHORDATA:  SUBPHYLUM  VERTEBRATA. 

Class  Mammalia 205 

Order  Monotremata 206 

Order  Marsupialia 206 

Order  Insectivora 208 

Order  Chioptera 210 

Order  Carnivora 211 

Order  Rodentia 227 

Order  Edentata 260 

Order  Primates 262 

Order  Ungulata 263 

Order  Sirenia 274 

Order  Cetacea 2  74 

REFERENCES 286 

INDEX.  .                                  293 


LIST  OF  ILLUSTRATIONS 

FIGURE  PAGE 

1.  Ameba i 

2.  Trypanosome 3 

3.  Victim  of  sleeping  sickness 4 

4.  Diagram  to  illustrate  the  life-history  of  the  malarial  parasite 5 

5.  Negri  bodies 8 

6.  Tests  of  foraminifera 10 

7.  Colony  of  simple  sponges 1 1 

8.  Colony  of  Obelia 15 

9.  Three  Scyphozoa 16 

10.  Sea  anemone .' 17 

11.  Ctenophora 18 

12.  An  atoll 19 

13.  Starfish 21 

14.  Sea  urchin 22 

15.  Sea  urchin  with  spines  removed 23 

16.  Sea  cucumber 23 

17.  Serpent  star 24 

18.  Crinoid 25 

19.  Planaria 26 

20.  Human  tapeworm 28 

21.  Liver  fluke 29 

22.  Parts  of  Ascaris  lumbricoides 31 

23.  Cross  section  of  Ascaris  lumbricoides 32 

24.  Dissection  of  Ascaris  lumbricoides 33 

25.  Hookworm 34 

26.  Trichinella  spiralis 37 

27.  Leech 41 

28.  Diagram  of  leech 42 

29.  Dissection  of  oyster 46 

30.  Bed  of  marketable  oysters 48 

31.  Oyster  shell  and  pipe,  with  attached  oysters 49 

32.  Tangle  for  collecting  starfish,  etc 50 

33.  Oyster  tongs  in  use 51 

34.  Oyster  dredge  in  use 52 

35.  Long-neck  clam 53 

36.  Clam  beach  and  rake 54 

37.  Long-neck  clams  from  one  square  foot  of  flat 55 

38.  Hard-shell  clam 56 

xiii 


XIV  LIST    OF    ILLUSTRATIONS 

FIGURE  PAGE 

39.  Scallop 56 

40.  Salt-water  mussel 57 

41 .  Abalone 58 

42.  Window  shell 59 

43.  Murex ;  ,v '..".  . 60 

44.  Drilled  shell  of  pearl  mussel 63 

45.  Ship-worm 64 

46.  Octopus 64 

460.  Squid 65 

47.  Chiton 66 

48.  Dentalium 66 

49.  Cyclops 68 

50.  Goose  barnacle 69 

51.  Acorn  barnacle 70 

52.  Peripatus 70 

53.  Crayfish , 75 

54.  Rock  crab 77 

55.  Shrimp 78 

56.  Centipede 78 

57.  House  centipede 79 

58.  Millipede 79 

59.  "Tarantula"  spider 80 

6c.  Black  widow  spider 81 

6r.  Scorpion 82 

62.  Acarina 82 

63.  King  crab 84 

64.  Yellow-fever  mosquito. 85 

65.  Culex  and  Anopheles  mosquitoes 86 

66.  Larvae  of  Anopheles 87 

67.  Eggs  and  larvae  of  Culex 88 

68.  Larva  and  pupa  of  Culex 89 

69.  House-fly 90 

70.  Wing  of  stable-fly 91 

71.  Wing  of  house-fly 91 

72.  Part  of  leg  of  house-fly 92 

73.  Eggs  of  house-fly 93 

74.  Maggot  trap  for  house-flies 95 

75.  Termites 96 

76.  Work  of  termites  in  walnut  wood 97 

77.  Work  of  termites  in  book 98 

78.  Clothes  moth 101 

79.  Ichneumon  fly  and  host 105 

80.  Lateral  view  of  Amphioxus 108 

81.  Three  Cyclostomes 109 

82.  Dog-fish in 


LIST    OF    ILLUSTRATIONS  XV 

FIGURE  PAGE 

83.  Electric  ray ...    112 

84.  Sword-fish •    n8 

85.  Sturgeon •    HQ 

86.  Metamorphosis  of  frog •    124 

87.  Mud-puppy,  Necturus. 125 

88.  Hellbender,  Cryptobranchus 125 

89.  Spotted  salamander ...    126 

90.  Tree  frog ...    127 

91.  Common  bullfrog' •  •    128 

92.  Leopard  frog •  •  •  ,I29 

93.  Spring  frog -131 

94.  American  toad *32 

95.  Green  turtle ,- ,  *..  •    *38 

96.  Carapace  of  diamond-back  terrapin .14° 

960.  Pen  of  diamond-back  terrapins 142 

97.  Common  snapping  turtle • •    145 

98.  Common  soft-shelled  turtle .    146 

99.  Hawk's  bill  turtle .    U9 

100.  Common  swift ...  151 

101.  Iguana -  •  i52 

102.  Dissected  head  of  rattlesnake 154 

103.  Skull  of  a  pit  viper ...  i55 

104.  Cotton-mouth  moccasin .  .  158 

105.  Copperhead •  •  •  160 

106.  Diamond  rattler ...  161 

107.  Common  water  snake 163 

108.  Blacksnake ...  165 

109.  Common  bull  snake 168 

no.  Common  king  snake 169 

in.  Skins  of  alligator 1 73 

112.  Archaeopteryx , 179 

1 13.  Kiwi 1 80 

1 14.  African  ostrich 181 

115.  Plucking  an  ostrich r 183 

1 16.  American  egret 187 

117.  California  quail 188 

118.  Hairy  woodpecker 190 

119.  Great  horned  owl 191 

120.  Barn  owl 192 

121.  Cooper's  hawk 193 

122.  Four  seed-destroying  sparrows 196 

1 23.  Bird  house 199 

1 24.  Bird  house 199 

125.  Bird  house 199 

-126.  Martin  house 201 


XVI  LIST   OF   ILLUSTRATIONS 

FIGURE  PAGE 

127.  Window  food  shelf 202 

1 28.  Feeding  box  on  pole 203 

1 29.  Feeding  box  on  pole 204 

130.  Feeding  box  on  pole 204 

131.  Opossum , 207 

132.  Kangaroo ..,.-;..  208 

133.  Common  mole 209 

134.  Little  brown  bat 210 

135.  Karakul  sheep  and  lamb •. .' 215 

136.  Black  fox 216 

137.  Plan  for  fox  ranch 217 

138.  Fox  kennel  and  pen 218 

139.  Canadian  otters... 219 

140.  Mink 220 

141.  Skunk 221 

142.  Muskrat 222 

143.  Beaver 223 

144.  Fur-seal  rookery 225 

145.  Skull  of  woodchuck 227 

146.  Brown  rat 229 

147.  Rat  poster 232 

i47a.  Rat  poster 233 

148.  Rat-proofing  in  barn 234 

149.  Rat-proofing  a  wooden  building 236 

150.  Rat-proof  corn  crib , 237 

151.  All-metal  guillotine  rat  trap 238 

152.  Wooden  base  guillotine  rat  and  mouse  traps 239 

153.  Wire  cage  rat  trap 239 

154.  Barrel  rat  trap 240 

155.  Rat  shields  for  ships'  hawsers 242 

156.  Meadow  and  pine  mice 246 

157.  Apple  tree  girdled  by  mice 247 

158.  Pile  of  mouse  skulls  from  owl  pellets 250 

159.  Mound  of  ground  squirrel 252 

160.  Poisoned  ground  squirrels 253 

161.  Cottontail  rabbit 255 

162.  Section  of  Walmsley  rabbit  trap 256 

163.  Walmsley  trap  set  under  a  fence 256 

164.  Pocket  gopher .258 

165.  Section  of  gopher  tunnels 258 

166.  Porcupine .  .  259 

167.  Two-toed  sloth ...  260 

168.  Great  anteater 261 

169.  Armadillo ...                                      .  .  261 

170.  Gorilla „ 262 


LIST    OE   ILLUSTRATIONS  XV11 

FIGURE  PAGE 

171.  Monkey 263 

172.  Stomach  of  ruminant 264 

173.  African  elephant 266 

174.  American  bison 268 

175.  Alaska  moose 270 

176.  Elk 271 

177.  Caribou 273 

178.  Manatee 275 

179.  Skull  of  Greenland  whale 276 

180.  Dolphin 276 

181.  Sperm  whale 277 

182.  Sulphur-bottom  whale 277 

183.  Finback  whale 278 

184.  Humpback  whale 278 

185.  Finback  whale 279 

186.  Whale  steamer 279 

i860.  Whaling  station 280 

1866.  Steamer  towing  whales 281 

187.  Head  of  sulphur-bottom  whale 282 

188.  Raising  a  side  of  whalebone  into  a  ship .'....  283 

189.  Bundles  of  whalebone 284 


ECONOMIC  ZOOLOGY 


CHAPTER  I 
PROTOZOA 

The  phylum  Protozoa  includes  a  large  number  of  small  animals; 
they  are  mostly  of  microscopic  size,  though  some  of  them  are  easily 
seen  with  the  naked  eye.  They  all  consist  of  but  a  single  cell,  which 
is  sometimes  quite  complex. 

The  phylum  is  usually  divided  into  four  classes  according  to  the 
presence  or  absence  of  organs  of  locomotion  and  the  character  of  these 
organs,  if  present.  These  classes  are  as  follows: 

I.  Rhizopoda,  with  pseudopodia,  Fig.  i.  II.  Mastigophora,  with 
flagella,  Fig.  2.  III.  Sporozoa,  non-motile,  in  adult  condition  at 


PIG.   i. — Ameba.     cv,    contractile    vacuole;    ec,    ectosarc;    en,   endosarc;  fv,   food 
vacuole;  n,  nucleus;  p,  pseudopodia.     Highly  magnified. 

least,  Fig.  4.  IV.  Infusoria,  with  cilia.  Of  these  classes  the  first 
three  are  of  economic  importance  and  will  be  discussed  in  turn,  the 
Infusoria  are  of  little  importance,  though  some  of  them  may  be  con- 
cerned in  certain  intestinal  diseases. 

Rhizopoda. — Without  further  classification  several  representatives 
of^this  class  will  now  be  discussed. 

Ameba,  Fig.  i .  There  are  two  (possibly  more)  species  of  this  familiar 
genus  that  are  found  in  the  human  intestine,  Ameba  or  Entameba  coli 


ZOOLOGY 

and  E<  histetytiea  vr:  dyswnleria.  Authorities  differ  as  to  whether 
they  should  be  considered  as  belonging  to  the  genus  Ameba  or  to  a 
distinct  genus. 

E.  coliis  commonly  found  in  the  human  intestine;  as  many  as  60 
per  cent,  of  the  feces  examined  in  one  instance,  showing  this  species; 
it  is  apparently  not  pathogenic. 

E.  histolytica  is  supposed  to  be  the  cause  of  at  least  one  kind  of 
Amebic  or  Oriental  Dysentery;  and  one  of  the  first  warnings  one 
receives  in  going  to  the  Orient  is  against  eating  raw  fruits  or  vegetables 
unless  they  have  been  peeled  or  have  been  thoroughly  washed.  This 
entameba  burrows  between  the  cells  of  the  digestive  epithelium  or, 
perhaps,  into  the  cells  themselves,  by  its  ameboid  activities.  (E. 
buccalis,  another  species,  is  found  in  carious  teeth.) 

Rabies,  or  hydrophobia,  one  of  the  most  fatal  of  the  diseases  to  which 
man  is  subject,  is  transmitted,  usually  by  the  bite  of  a  dog  or  some  other 
animal.  It  was  formerly  thought  that  dogs  "went  mad"  from  heat, 
especially  during  the  "dog  days;"  from  having  tin  cans  tied,  by  mis- 
chievous boys,  to  their  tails;  and  from  other  causes.  It  is  probable 
that  animals  never  "go  mad;"  they  become  infected  with  rabies  only 
through  the  bite  of  some  other  animal  suffering  with  the  disease.  In 
the  nerve  cells  of  the  brain  and  spinal  cord  of  animals  suffering  from 
rabies  are  found,  by  proper  staining  methods,  minute  bodies  of  variable 
size  known  as  Negri  bodies  or  neurocytes  hydrophobiae,  Fig.  5.  If  not 
the  cause  of  the  disease,  as  many  think,  they  are,  at  least,  a  constant 
accompaniment  of  it;  and  it  is  now  possible  by  them  to  tell,  by  the 
examination  of  the  brain  of  the  suspected  animal,  whether  the  human 
victim  should  be  given  the  antirabic  treatment  or  not.  Formerly 
it  took  from  two  to  three  weeks  to  determine  whether  an  animal  were 
"mad;"  now  the  determination  can  be  made  in  half  an  hour,  which 
is  obviously  a  wonderful  advantage  in  deciding  whether  to  administer 
the  Pasteur  treatment. 

Negri  regarded  the  bodies  that  bear  his  name  as  Protozoa,  belonging 
to  the  class  Sporozoa.  Other  workers  declare  them  to  be  Rhizopods — 
the  class  under  discussion. 

In  the  skin  of  persons  suffering  from  smallpox  are  found  small 
bodies  that  are  considered  by  many  to  be  Rhizopods  and  to  be  the  cause 
of  the  disease.  Possibly  still  other  less  well-known  diseases  may  be 
due  to  the  Rhizopods. 


PROTOZOA  o 

Foraminifera  form  an  order  of  the  class  Rhizopods  that  is  of  some 
economic  importance  because  of  the  limestone  that  is  formed  from  the 
dead  calcareous  shells  or  tests,  Fig.  6.  One  of  the  best  known  of  the 
foraminifera  is  Globigerina.  This  form,  which  is  about  the  size  of  a 
small  pin-head,  is  widely  distributed  over  the  ocean,  and  the  shells  of 
the  dead  animals  fall  to  the  sea  bottom  where  they  form  the  so-called 
Globigerina  ooze,  that  solidifies  to  form  gray  chalk. 

Nummulites  are  the  largest  of  the  foraminifera,  sometimes  reach- 
ing the  size  of  a  silver  dollar,  which  they  resemble  somewhat  in  shape. 
The  pyramids  of  Egypt  are  built  largely  of  nummulitic  limestone. 

Radiolaria  are  an  order  of  Rhizopods  having  usually  a  complicated 
skeleton  of  silica.     They  are  all  marine  forms  and  after  death  their 
skeletons  settle  to  the  sea  floor  as  radiolarian 
ooze,  sometimes  hundreds  of  feet  thick,  that 
forms  flint  or  quartz. 

Mastigophora. — Of  the  pathogenic  flagel- 
lata  the  best  known  genus  is  Trypanosoma, 
of  which  there  are  several  species,  parasitic 

n     -,  e          .    i  ~  PIG.  2. — A  try panosome ; 

in  all  classes  of  vertebrates  up  to  man.     One    a  parasitic  flagellate. 
of  the  most  terrible  diseases  to  which  man  is    Greatly  magnified, 
subject   is   trypanosomiasis  or  sleeping  sick- 
ness, which  of  late  years  has  been  sweeping  over  Africa  and  destroying 
the  natives  by  the  hundreds  of  thousands.     It  is  said  to  be  fatal  in 
100  per  cent,  of  the  cases,  tho  headway  is  being  made  toward  discover- 
ing a  cure. 

The  organism  concerned  is  T.  Gambiense,  Fig.  2,  which  is  introduced 
into  the  human  blood  by  the  bite  of  the  tsetse  fly,  Glossina  palpalis. 
Whether  the  protozoan  undergoes  a  part  of  its  life  history  in  the  body  of 
the  fly  or  is  merely  carried  mechanically  is  a  debated  question;  possibly 
there  may  be  another  and  an  unknown  host;  at  any  rate  it  has  been 
found  that  the  spread  of  the  disease  may  be  checked  by  cleaning  up 
the  brushy  areas  along  streams  and  water-courses. 

Just  how  the  trypanosoma  produces  its  ill  effects  is  uncertain; 
it  may  be  found  in  the  blood,  where  it  destroys  the  red  cells,  and  in  the 
cerebrospinal  fluid.  The  disease,  which  may  run  its  course  in -a  few 
months  or  last  for  years,  exhibits  various  symptoms,  the  most  evident 
of  which  is  a  marked  drowsiness  or  coma  that  has  given  the  popular 
name  to  the  disease;  the  patient  loses  all  desire  for  food  and  gradually 


4  ECONOMIC   ZOOLOGY 

wastes  away  and  dies  in  a  terribly  emaciated  condition,  Fig.  3.  While 
it  is  the  natives  of  Africa  that  chiefly  suffer,  the  organism  attacks 
whites  as  well  as  blacks,  and  several  investigators  have  sacrificed  their 
lives  in  studying  the  disease. 

One  of  the  most  serious  and  fatal  diseases  of  domestic  animal  in  the 
Orient  is  Surra.  This  disease  is  probably  caused  by  a  Trypanosome 
introduced  into  the  blood  by  the  bite  of  a  fly. 

Another  serious  disease  of  cattle  in  this  country  is  Texas  fever.  The 
organism  here,  Babesia,  is  considered  by  some  workers  to  be  a  flagel- 
late, by  others  to  belong  to  the  next  order,  the  Sporozoa. 

How  the  cattle  "caught"  the  disease  was  a  great  mystery  until 
Smith  and  Kilborn  discovered  that  the  germ  is  carried  from  animal  to 
animal  by  a  tick.  The  adult  female  tick  is  fertilized  while  hanging 


PIG.  3. — Victim    of    sleeping    sickness,     shortly    before    death.      (After    Calkins, 

Protozoology.) 

to  the  skin  of  the  ox;  she  gorges  herself  with  the  infected  blood  of  her 
host  and  falls  to  the  ground,  where  she  lays  an  enormous  number  of 
eggs.  Each  larva,  when  it  hatches,  is  supplied  with  a  little  of  the  in- 
fected blood  ;*it  crawls  upon  a  blade  of  grass  where  it  will  die  unless 
another  ox  brushes  against  the  grass,  when  the  young  tick  may  suc- 
ceed in  attaching  itself  to  the  hair  of  this  ox;  here  it  develops  into  an 
adult  and  infects  its  new  host  the  first  time  it  feeds  upon  its  blood. 
No  wonder  the  spread  of  the  disease  was  so  mysterious,  when  one 
animal  could  infect  another  without  ever  having  been  within  a  hundred 
miles  of  it. 

Sporozoa. — Of  these  very  minute  Protozoa  the  most  important, 
perhaps,  is  the  genus  Plasmodium,  of  which  there  are  probably  several 


PROTOZOA 


Development  of 
Parasite  in 


Some  may  be  taken 

into  the  stomach 
\  J*_       of  the  Mosquito  when 
it  bites 


PIG.  4. — Diagram  to  illustrate  the  life-history  of  the  malarial  parasite;  i,  is 
a  red  blood  corpuscle;  2  to  7  show  the  development  of  the  parasite  in  the  corpuscle; 
a,  b,  c,  d  and  a',  b',  c',  d'  and  e  show  the  development  of  the  parasite  in  the  stomach 
of  the  mosquito;  /,  g,  h,  i,  show  the  development  in  the  capsule  on  the  outer  wall  of 
the  stomach  of  the  mosquito;  k  is  the  salivary  gland  of  the  mosquito.  Greatly 
enlarged.  (After  Doane,  Insects  and  Disease.) 


O  ECONOMIC    ZOOLOGY 

species.  This  is  the  organism  that  causes  one  of  the  oldest  and  most 
widely  distributed  diseases  of  man,  malaria,  which  was  the  first  disease 
that  was  proven  to  be  directly  caused  by  a  protozoan  parasite.  Until 
near  the  beginning  of  the  present  century  both  the  cause  and  the  mode 
of  transmission  of  malaria  were  unknown,  though  Lancisi,  in  1718, 
ventured  the  statement  that  mosquitoes  or  gnats  might  introduce 
certain  poisonous  substances,  found  in  swampy  regions,  into  the  human 
blood  and  thus  cause  malaria.  It  has  been  recognized  for  ages  that 
malaria  was  more  prevalent  in  damp  and  swampy  regions  and  the 
disease  owes  its  name — Mai-aria — to  the  commonly  held  idea  that  it 
was  due  to  bad  air  or  miasmas  found  hanging  over  swamps  and  such 
places;  it  was  also  generally  thought  that  the  disease  could  be  contracted 
by  drinking  bad  water. 

In  i88iDr.  La veran  discovered  a  curious  new  parasite  in  the  blood 
of  malarial  patients,  which  he  claimed  was  the  cause  of  the  disease. 
This  discovery  did  not  attract  much  attention  until  some  years  later 
when  Laveran  and  Manson  independently  suggested  that  the  germ  might 
be  transmitted  to  man  by  the  bite  of  some  blood-sucking  insect. 
After  years  of  investigation  Major  Ronald  Ross,  of  the  English  army, 
finally  worked  out  the  life  history  and  proved  that  the  insect  re- 
sponsible for  the  transmission  of  human  malaria  is  a  mosquito  belonging 
to  the  genus  Anopheles,  while  bird  malaria  is  transmitted  by  the  genus 
Culex. 

The  life-history  of  the  sporozoan  is  essentially  the  same  in  the  three 
types  of  the  fever,  the  main  difference  being  the  different  lengths  of  the 
developmental  periods,  the  tertian  fever  producing  the  attack  or 
chill  every  48  hours,  the  quartan  fever  every  72  hours  and  the  pernicious 
fever  every  day. 

The  whole  life-history  in  both  hosts,  man  and  anopheles,  is  briefly  as 
follows:  the  organisms  are  introduced  into  the  blood  when  the 
mosquito  bites.  These  minute,  elongated  sporozoa  move  about  in 
the  blood  plasma  and  finally  enter  the  red  blood  cells.  According 
to  some  authors  they  do  not  actually  enter  the  cells,  but  it  is  difficult 
to  see  how  the  following  processes  could  take  place  unless  they  do. 
In  the  blood  cells  they  grow  and  give  off  poisons  that  are  contained 
within  the  cells.  At  the  end  of  their  developmental  period,  48  hours, 
for  example,  in  the  tertian  fever,  they  break  down  into  numerous  spores, 
and  it  is  the  escape  from  the  corpuscles  of  these  countless  spores,  together 


PROTOZOA  7 

with  the  above  mentioned  toxins,  that  causes  the  chill.  This  process 
of  sporulation,  which  continues  at  very  regular  intervals,  sets  free  into 
the  blood  three  types  of  spores  which,  for  convenience  may  be  termed 
male,  female  and  neutral.  If,  now,  a  culex  mosquito  sucks  the  blood 
containing  these  spores,  they  are  all  digested  along  with  the  blood,  in 
the  mosquito's  stomach;  if,  however,  it  be  an  anopheles,  instead  of  some 
other  genus,  that  sucks  the  blood,  different  results  follow.  In  the 
anopheles'  stomach  the  neutral  forms  are  digested,  along  with  the 
blood,  but  the  male  and  female  cells  conjugate  and  form  a  cyst  or 
nodule  in  the  wall  of  the  stomach.  This  cyst  breaks  down  into  many — 
perhaps  ten  thousand — tiny  sporozoites,  and  as  there  may  be  hundreds 
of  cysts  in  one  mosquito  the  number  of  sporozoites  is  enormous.  After 
ten  days  or  more  these  sporozoites  collect  in  the  mosquito's  salivary 
glands,  where  they  may  live  for  two  or  three  weeks,  during  which  time, 
if  the  mosquito  bite  a  human  being  she  will  inject  into  the  wound  some 
of  the  sporozoites,  and  the  life  cycle  is  begun  again  in  another  victim. 
Several  persons  may  be  infected  by  the  same  mosquito. 

It  has  been  found  that,  under  certain  conditions,  the  sporozoon 
may  remain  dormant  in  the  spleen  or  bone  marrow  for  months  or 
years,  where  it  can  resist  the  action  of  quinine,  the  universally  used 
specific  for  malaria;  under  favorable  conditions  it  may  resume  its 
activities  and  the  person  will  suffer  a  relapse. 

Not  only  has  this  life-history  of  the  parasite  been  very  carefully 
worked  out,  but  numerous  practical  tests  have  been  made  that  prove 
very  conclusively  that  malaria  is  not  " caught"  from  mists,  drinking 
water,  etc.  For  example,  wherever  malaria  is  found,  excepting  sporadic 
cases  that  may  be  introduced  from  other  regions,  the  anopheles  is  found. 
There  are  sections  where  this  mosquito  exists  without  malaria,  simply 
because  nobody  has  introduced  the  disease  into  that  region.  The 
reason  for  the  prevalence  of  malaria  in  swampy  regions  is,  of  course, 
that  it  is  in  such  places  that  mosquitoes  abound. 

The  experiments  of  Grassi,  the  Italian,  will  serve  as  an  example  of 
many  similar  experiments.  "In  1900  he  received  permission  from  the 
government  to  experiment  on  the  employees  of  a  piece  of  railroad  that 
was  being  built  through  a  malarial  region.  This  was  divided  for  the 
purposes  of  the  experiment  into  three  sections,  a  protected  zone  in  the 
middle  and  an  unprotected  zone  at  each  end.  Those  working  in  the 
protected  zone  had  their  houses  completely  screened  and  no  one  was 


8 


ECONOMIC   ZOOLOGY 


allowed  out  of  doors  after  sunset  except  they  were  protected  with  veils 
and  gloves.  Early  in  the  season  they  were  all  given  doses  of  quinine 
to  prevent  auto-infection.  In  the  unprotected  zones  no  screens  were 
used  and  everyone  was  allowed  to  go  without  special  protection.  The 
result  for  the  summer  was  that  there  were  no  new  cases  of  fever  in  the 
protected  zone.  In  the  unprotected  zones  practically  all  had  the  fever 
as  usual." 


3.  *• 


to. 


FIG.   5. — Negri   bodies   or  neurocytes  hydrophobias,  in  different  stages  of  chromatic 
distribution.     Greatly  magnified.     (From  Calkins,  Protozoology,  after  Negri.) 

Yellow  fever,  one  of  the  most  dreaded  of  human  diseases  is  now 
known  to  be  transmitted  by  the  bite  of  a  mosquito,  Stegomyia,  just 
as  is  malaria  by  Anopheles.  While  the  germ  of  the  disease  has  not 
been  seen  there  are  reasons  for  thinking  it  may  be  a  sporozoon  of 
extremely  minute  size,  so  that  a  brief  account  of  the  disease  may  be  in 
place  here. 


PROTOZOA  9 

In  1900,  during  the  American  occupation  of  Cuba,  the  yellow  fever 
became  so  prevalent  there  that  a  yellow  fever  commission  of  medical 
officers  was  ordered  to  study  the  disease.  Dr.  Finlay  of  Havana 
had  claimed  that  the  disease  was  transmitted  by  the  bite  of  a  mosquito, 
and  the  commission  decided  to  prove  or  disprove  this  theory.  No 
braver  nor  more  useful  piece  of  work  has,  perhaps,  ever  been  done 
than  that  of  the  members  of  this  commission — Drs.  Reed,  Carroll, 
Lazear  and  Agramonte.  The  crucial  test  was  to  let  an  infected 
mosquito — that  is,  one  that  had  bitten  a  yellow  fever  patient — bite 
a  non-immune  person  to  see  if  the  disease  would  thus  be  transmitted. 
Dr.  Carroll  allowed  himself  to  be  bitten  by  such  a  mosquito  and  in  due 
time  developed  the  disease,  so  that  he  was  the  first  person  to  whom 
it  was  proven  that  the  mosquito  had  carried  the  disease.  His  heroism 
fortunately  did  not  cost  him  his  life,  but  Dr.  Lazear,  who  was  accident- 
ally bitten,  died  in  a  few  days.  Other  volunteers  allowed  themselves 
to  be  experimented  upon,  and,  when  the  conditions  were  right,  developed 
the  disease.  It  was  found  that  it  is  only  during  the  first  three  days 
of  the  disease  that  a  mosquito  may  be  infected  by  biting  a  yellow 
fever  patient,  and  that  12  days  must  elapse  before  this  mosquito  is 
capable  of  infecting  another  person.  It  is  even  claimed  that  the 
mosquito  may  transmit  the  infecting  power  to  her  offspring.  Various 
experiments  like  the  one  quoted  above  for  malaria  were  tried  with 
yellow  fever.  For  example,  a  number  of  non-immunes  lived  for  three 
weeks  in  a  mosquito-proof  house,  where  they  were  supplied  with 
clothing  and  other  articles  from  a  yellow  fever  hospital.  They  even 
slept  between  soiled  sheets  from  a  bed  which  a  yellow  fever  patient 
had  occupied.  None  of  them  developed  the  disease.  When  some  of 
these  men  were  later  inoculated  they  developed  the  disease,  showing 
that  they  were  not  immunes. 

Thus  it  was  conclusively  proven  that  yellow  fever  is  transmitted 
by  the  bite  of  the  Stegomyia  mosquito  and  in  that  way  alone.  The 
effect  of  this  discovery  upon  the  health  of  Havana,,  New  Orleans,  the 
Canal  Zone  and  other  pest-ridden  places,  is  known  to  all.  The  problem 
resolved  itself  simply  into  cleaning  up  the  swamps,  covering  the  cisterns, 
etc.,  thus  exterminating  the  mosquitoes.  The  methods  employed  in 
this  work  will  be  discussed  in  the  section  dealing  with  insects. 

The  terrible  mortality  among  the  laborers,  engineers,  doctors  and 
nurses,  while  the  French  were  at  work  upon  the  Panama  Canal,  was 


10 


ECONOMIC    ZOOLOGY 


almost  eliminated  while  the  Americans  were  at  work 
Canal  Zone  is  now  as  healthy  as  almost  any  part  of  the 

Another  disease  that  may  be  caused  by  a  protozoan 
quite  certainly  transmitted  by  one  or  more  species 
dengue  or  break-bone  fever,  common  in  many  parts  of 
is  a  disease  that  causes  suffering,  but  seldom  death. 

Kala-azar  or  dum-dum  fever  is  a  very  dangerous 
that  is  supposed  to  be  due  to  a  protozoan  parasite, 
man  by  the  common  bedbug  of  India. 


there,  and  the 
United  States. 
parasite,  and  is 
of  mosquito  is 
the  tropics.     It 

tropical  disease 
transmitted  to 


FIG.  6. — Tests   of  foraminifera,   magnified   about    10   diameters. 

Protozoology.) 


(After   Calkins, 


Infusoria. — This  well-known  and  zoologically  interesting  class  of 
ciliated  protozoa,  represented  by  the  commonly  studied  form  Para- 
mecium,  is  of  little  economic  importance.  Infusorial  earth,  used 
in  making  dynamite,  is  not  made  up  of  infusoria,  as  might  be  ex- 
pected, but  of  the  tests  of  diatoms  and  other  forms. 

A  few  of  the  infusoria  may  be  concerned  in  some  of  the  intestinal 
diseases. 


CHAPTER  II 
PORIFERA 

The  porifera  or  sponges  are  plant-like  aquatic  animals,  all  but  one 
family  of  which  are  marine. 

The  typical  or  primary  form  of  a  sponge  is  cylindrical  or  vase 
shaped,  Fig.  7,  but  in  nearly  all  cases  a  process  of  branching  has  con- 
verted the  simple  vase  into  a  highly  complex  organism  or  colony. 
In  the  simple  sponge  the  central  cavity  opens  to  the  exterior  by  a 


PIG.  7. — A  colony  of  simple  sponges.      X/£- 

single,  large,  excurrent  opening  or  osculum,  and  by  numerous  minute 
inhalent  openings  or  pores,  Fig.  7.  The  pores  lead  into  more  or  less 
complicated  systems  of  canals  which  are  lined  with  vibrating  flagella 
that  cause  currents  of  water  to  flow  through  the  canals  into  the  central 
cavity  and  thence  out  of  the  osculum.  It  is  these  currents  of  water 
that  supply  the  organism  with  food  and  oxygen,  and  at  the  same  time 


12  ECONOMIC   ZOOLOGY 

remove  waste.  Between  the  outer  layer  of  cells,  the  ectoderm,  and  the 
inner  layer,  the  entoderm,  is  a  more  or  less  gelatinous  layer,  the  meso- 
derm,  in  which  are  found  the  skeletal  elements  that  give  the  sponge 
its  definite  form.  In  the  commercial  sponges,  of  particular  interest 
here,  the  skeleton  consists  mainly  of  a  complicated  network  of  horny 
fibres  of  a  substance  called  spongin,  which  is  stiff  and  hard  when  dry, 
but  is  more  or  less  flexible  when  wet. 

In  other  sponges  the  skeletal  elements  are  tiny  structures  of  various 
shapes,  called  spicules,  which  may  be  either  calcareous  or  silicious. 

Sponges  multiply  asexually  by  budding  and  by  means  of  asexual 
spores  or  gemmules;  and  sexually  by  means  of  ova  and  sperm.  The  fer- 
tilized ovum  develops  into  a  ciliated,  free-swimming  larva  that  later 
becomes  attached  and  develops  into  the  plant-like  adult  sponge. 

In  the  ordinary  commercial  sponges  the  process  of  budding  and 
branching  has  gone  so  far  that  it  is  difficult  to  recognize  the  primary 
vase-shaped  individual  in  the  complicated  mass  with  dozens  or  hundreds 
of  oscula  and  thousands  of  pores. 

In  some  of  the  older  texts  the  sponges  were  classified  under  the 
phylum  ccelenterata,  but  they  are  now  generally  placed  in  a  separate 
phylum.  Fossil  sponges  are  found  in  all  geological  formations  from 
the  Cambrian  upward.  Although  found  in  all  seas  and  at  almost 
all  depths,  it  is  in  tropical  and  subtropical  waters  they  especially 
abound. 


"The  sponges  of  commerce  come  from  the  eastern  Mediterranean  Sea, 
the  West  Indies,  and  the  coasts  of  Florida  and  Central  America.  In  the 
Grecian  Archipeligo,  Crete,  Cyprus,  on  the  coasts  of  Asia  Minor,  Syria, 
Barbary,  and  the  Bahama  Islands,  sponge  fisheries  constitute  a  very  im- 
portant industry.  The  finest  sponges  are  obtained  in  Turkish  waters.  The 
fishing  season  commences  in  May  and  closes  in  September  or  October. 
Diving  is  practised,  and  is  carried  on  in  a  rude,  primitive  manner.  The 
diver,  who  has  no  dress,  siezes  hold  of  a  large  stone,  to  which  a  line  is  attached, 
and  sinks  by  means  of  it  to  a  depth  varying  from  30  to  180  (?)  feet.  Keep- 
ing hold  of  the  rope,  he  tears  the  sponges  off  the  rocks  within  his  reach,  and 
places  them  in  a  net;  when  he  secures  a  netful  he  signals  by  means  of  the  rope 
to  be  drawn  up. 

"Modern  diving  dresses  have  been  successfully  introduced  in  some 
places.  The  West  Indian  trade  is  annually  increasing,  and  the  fishing  in- 
dustry gives  employment  to  500  boats  and  2000  persons.  The  Bahamas 
and  the  coast  of  Florida  are  the  best  fishing  grounds. 


PORIFERA  13 

"Florida  is  the  only  State  in  the  Union  which  has  a  sponge-fishery, 
and  there  it  is  confined  to  the  southwestern  part  of  the  coast,  along  the  reefs, 
and  to  the  extensive  rocky  shoals  that  lie  between  St.  Mark's  and  Anclote 
Keys.  The  former  is  known  as  the  Key  ground,  with  its  centre  at  Key 
West,  the  latter  as  the  bay  ground,  with  its  centre  at  Tampa  Bay. 

"  Nearly  all  the  sponges  used  in  the  United  States  were  brought  from 
the  Mediterranean  till  1852,  when  attention  was  called  to  the  immense 
numbers  that  were  growing  in  Florida  waters.  As  soon  as  it  was  found  that 
the  quality  of  these  compared  favorably  with  those  of  Europe  the  merchants 
and  fitters-out  of  vessels  of  Key  West  engaged  very  actively  in  the  business 
of  placing  them  on  the  market.  At  first  the  best  qualities  were  bought 
from  the  fisherman  at  10  cents  a  pound.  As  Mediterranean  sponges  became 
scarce  and  costly  the  Florida  sponges  came  more  and  more  into  demand, 
and  their  value  increased  proportionately.  After  about  18  years'  fishing  on 
the  known  ground  the  supply  began  to  fail.  Then,  in  1870,  a  new  area  of 
ground,  larger  than  the  old  one,  was  discovered,  and  this  gave  a  new  impetus 
to  the  trade.  In  that  year  Appalachicola  sent  out  a  small  fleet  of  sponge 
vessels  which  has  since  been  largely  increased,  and  the  industry  has  been 
energetically  pursued  with  good  results. 

"The  methods  employed  in  the  fishery  differ  greatly  from  those  em- 
ployed in  the  Mediterranean.  Small  vessels,  carrying  crews  of  from  5  to  15 
men,  are  fitted  out  for  trips  of  from  four  to  eight  weeks  on  the  sponge  grounds. 
The  crews  are  paired  off  into  small  rowboats,  or  'dingies,'  to  catch  the 
sponges.  One  man  stands  in  the  stern,  skulling  the  boat,  while  the  other 
kneels  in  the  bottom  amidship,  leaning  over  the  side,  and  scans  the  bottom 
of  the  sea  by  means  of  a  water-glass.  When  a  sponge  is  sited  the  boat  is 
stopped,  and  the  kneeling  man  uses  a  three-pronged  hook,  attached  to  a 
slender  pole  30  to  50  feet  in  length,  to  secure  it.  Considerable  dexterity  is 
required  of  both  men.  To  cure  the  sponges  they  are  at  first  spread  about 
the  vessel's  deck  in  their  natural  upright  position  so  that  they  will  die,  and 
while  decomposing  allow  the  softened  animal  matter  to  run  off  freely.  When 
they  have  been  several  days  in  this  position  they  are  taken  to  the  shore  and 
thrown  into  the  water  in  little  pens,  called  "kraals' (corrals),  where  the  re- 
maining substance  is  soaked  and  squeezed  out,  after  which  the  sponges  are 
removed  at  intervals  and  beaten  with  a  stick  to  facilitate  the  process. 

"Although  most  actively  prosecuted  during  the  summer,  sponge  fishing  is 
now  followed  more  or  less  throughout  the  year,  the  vessels  beginning  their 
trips  during  January  and  working  the  different  beds  successively  from  north 
southward.  The  state  of  the  weather  greatly  affects  the  result  of  the  fishery. 
In  some  years  it  has  been  a  complete  failure,  while  in  others  it  has  been  very 
profitable,  always  owing  to  the  weather.  As  the  natural  beds  of  sponges 


14  ECONOMIC   ZOOLOGY 

have  become  scarcer  prices  have  advanced,  so  that  even  if  a  vessel  does  not 
secure  as  large  a  quantity  in  a  given  time  as  formerly  the  financial  result  is 
about  the  same. 

"  Several  varieties  of  sponges  are  caught  in  Florida  waters.  They  are 
first,  sheep's  wool,  which  sell  for  $2  to  $5  a  pound;  second,  yellow 
sponges,  which  sell  for  50  to  60  cents  a  pound;  and  third,  grass  sponges,  which 
are  coarse  in  texture  and  not  durable,  and  sell  for  15  to  25  cents  per  pound. 
Other  coarse  grades  are  boat  and  glove  sponges.  When  these  are  marketed 
they  are  cleaned  of  sand  and  shells,  and  then  pressed  into  small  bales  of 
100  to  120  pounds  each,  in  which  form  they  go  to  the  wholesale  dealers. 
The  yellow  sponge  especially  is  subjected  to  a  bleaching  process  to  improve 
the  color,  but  the  process  ordinarily  employed  greatly  weakens  the  fibre. 

"  Owing  to  the  rapidly  decreasing  supply  of  the  finer  grades  and  the 
rising  price  the  problem  of  propagating  sponges  artificially  has  been  taken 
up  seriously  by  the  United  States  Bureau  of  Fisheries.  It  has  been 
found  that  sponges  may  be  raised  successfully  both  from  the  egg  and  from 
cuttings  but,  owing  to  the  much  shorter  time  required  for  the  latter  to  reach  a 
marketable  size,  the  first  method  has  been  abandoned.  The  technical  prob- 
lems of  sponge  raising  have  been  largely  solved  and  there  is  every  promise 
that  .their  culture  on  a  commercial  scale  can  be  undertaken  in  the  near  future, 
and  that  the  depleted  grounds  will  be  restocked. 

"In  1900  the  Florida  sponge  fisheries  employed  2225  persons,  with  156 
vessels  and  other  apparatus  valued  at  $594,598.  The  product  aggregated 
418,125  pounds  of  all  kinds  of  commercial  sponges,  which  sold  for  $567,685. 
To  this  total  sheep  wool  sponges  contributed  181,131  pounds,  valued  at 
$483,263  "(36). 

Besides  the  above,  sponges  are  of  economic  importance  in  that  the 
silicious  spicules  of  some  species  form  large  flint  deposits.  Negatively, 
certain  sponges  are  of  economic  importance  because  of  their  destruc- 
tiveness  to  oyster  beds,  either  by  smothering  the  oysters  or  by  boring 
(certain  "Boring  Sponges"  have  this  curious  power)  through  their 
shells  and  thus  destroying  them. 


CHAPTER  III 
C(ELENTERATA 

This  phylum,  which  by  some  authors,  is  made  to  include  the  porif  era, 
though  important  scientifically,  is  one  of  the  least  importance  economic- 


Pic.  8. — Hydrozoa.  A,  part  of  a  colonial  species,  Obelia.  i,  ectoderm;  2, 
entoderm;  3,  mouth;  4,  ccelenteron;  5,  coenosarc;  6,  perisarc;  7,  hydrotheca;  8, 
blastostyle;  9,  medusa  bud;  10,  gonotheca.  B,  free-swimming  medusa  of  Obelia. 
i,  mouth;  2,  tentacles;  3,  reproductive  organs;  4,  radial  canals;  5,  statocyst.  C, 
larva  (planula)  of  Laomedea.  A,  Xio;  B  and  C,  more  enlarged.  (From  Hegner, 
College  Zoology;  A,  after  Parker  and  Haswell;  B,  after  Shipley  and  MacBride;  C, 
after  Parker  from  Allman.) 

ally.     It  includes  a  large  number  of  aquatic  forms,  mostly  marine^ 
and  mostly  soft,  even  jelly-like,  in  character;  they  are  radially  sym. 

15 


i6 


ECONOMIC   ZOOLOGY 


metrical  and  have  a  single  gastrovascular  cavity.  Many  of  them 
exhibit  two  stages — the  polyp  or  hydroid  form  and  the  medusa  or 
jelly-fish  stage.  They  possess  minute  sting  cells  or  nematocysts. 
They  are  usually  divided  into  three  or  four  classes,  as  follows: 

1.  Hydrozoa,  Fig.  8,  fresh  water  polyps  (Hydra,  for  example); 
hydroids   (Obelia);   small  jelly-fish   (Gonionemus);  and  a  few  stony 
corals. 

2.  Scyphozoa,  Fig.  9,  mostly  large  jelly-fish,  sometimes  as  large 
as  a  wash-tub. 

3.  Anthozoa  or  Actinozoa,  Fig.  10,  flower-like  sea  anemones,  corals, 
etc. 


cr 


A  EC 

FIG.  9. — Three  Scyphozoa.  Somewhat  reduced.  A,  Tessera  princeps.  B, 
Periphylla  hyacinthina.  C,  Charybdea  marsupialis.  (From  Hegner,  College  Zoology, 
after  Sedgwick  and  Haeckel.) 

4.  Ctenophora,  Fig.  n,  comb-jellies  or  sea  walnuts,  very  transparent 
jelly-like  forms  with  eight  bands  of  comb-like,  radially  arranged, 
ciliated  plates  or  locomotor  organs.  This  class  is  often  described 
as  a  distinct  phylum. 

Hydrozoa. — Except  for  comparatively  unimportant  sales  to  colleges 
and  museums  this  class  has  practically  no  economic  importance  so 
far  as  is  known;  possibly  they  may  help  destroy  organic  waste  particles 
in  the  water. 

Scyphozoa. — The  same  may  be  said  of  this  class,  except  that  the 
common  jelly-fish  or  sea  nettles  are  sometimes  a  pest  along  bathing 
beaches  on  account  of  the  painful  effect  upon  the  human  skin  of  their 


CCELENTERATA 


sting  cells.    Indeed,  a  few  forms,  for  example,  among  the  Cubomedusse, 
Fig.  9,  may  produce  quite  serious  results. 

Anthozoa. — This  is  the  most  important  of  the  ccelenterate  classes. 
Two  species  were  formerly,  probably  still  are,  eaten  in  Italy  under 


FIG.  10. — A  sea-anemone,  Metridium  marginatum,  partly  cut  away  so  as 
to  show  its  structure.  Xi.  i,  intermediate  zone;  2,  lip;  3,  siphonoglyph;  4, 
gullet;  5,  inner  edge  of  gullet;  6,  edge  of  mesentery;  7,  cavity  of  tentacle;  8,  inner 
ostium;  9,  outer  ostium;  10,  primary  mesentery;  n,  muscle  band  on  primary 
mesentery;  12,  abnormal  tertiary  mesentery;  13,  secondary  mesentery;  14,  tertiary 
mesentery;  15,  quaternary  mesentery;  16,  reproductive  gland;  17,  mesenterial 
filament;  18,  opening  for  mesenterial  filament.  (From  Hegner,  College  Zoology, 
redrawn  from  Linville  and  Kelly.) 

the  name  "Ogliole."  The  corals  are  the  most  important  of  the  cce- 
lenterates.  They  have  practically  the  structure  of  the  sea  anemones 
but  secrete  at  their  attachment  a  limestone  base  that  forms  the  well- 
known  coral  reefs,  so  dangerous  to  shipping  in  many  parts  of  the  tropics. 
2 


i8 


ECONOMIC  ZOOLOGY 


Occasionally,  these  reefs  take  a  circular  form  and  may  form  a  ring-like 
island  or  atoll,  Fig.  12,  with  an  enclosed  lagoon;  there  have  been  several 
theories  to  explain  the  formation  of  atolls.  In  many  parts  of  the 
Pacific  Ocean,  large  groups  of  islands,  have  been  formed  through  the 
action  of  the  coral  polyps,  and,  in  many  places,  large  deposits  of 
limestone  rock  owe  their  origin  to  these  small  animals. 

The  only  corals  that  have  any  value  as  such,  except  for  scientific 
purposes,  are  the  so-called    "precious  corals;"  they  are  usually  of  a 


C.SS. 


FIG.  ii. — Ctenophora.  Somewhat  enlarged.  A,  Hormiphora  plumosa;  side 
view,  i,  mouth;  2,  aboral  pole  with  sense  organ;  3,  funnel;  4,  paragastric  canal; 
5,  a  ciliated  band;  6,  canal;  7,  tentacular  pouch;  8,  tentacle;  9,  gelatinous  substance. 
B,  Pleurobranchia  pileus;  view  of  aboral  aspect,  showing  central  statocyst,  polar 
fields  (Pf),  and  8  ciliated  bands  (c.ss,  c.tr).  (From  Hegner,  College  Zoology,  A, 
from  Shipley  and  MacBride,  after  Chun;  B,  after  Lankester.) 

bright  red  or  pink  color  and  are  made  into  necklaces  and  other  orna- 
ments. These  corals  are  of  a  delicate  branching  type  and  are  collected 
mainly  in  the  Mediterranean  Sea,  especially  along  the  coasts  of  Africa, 
Italy,  Sardinia,  and  elsewhere,  even  as  far  as  the  Cape  Verde  Islands. 
They  were  formerly  thought  to  have  medicinal  value  and  to  be  able  to 
ward  off  danger  and  are  still  worn  by  superstitious  Italians  to  keep 
off  the  "evil  eye." 

Precious  coral  has    been  used  in  these  ways  since  remote  times; 


CCELENTERATA  .  1 9 

the   Gauls   ornamented   their   weapons   with   the   material  until  the 
oriental  demand  became  so  great  as  to  use  up  the  entire  supply. 

A  cheap  variety  of  precious  coral  is  collected  in  Japan;  it  is  also 
found  off  the  coasts  of  Ireland  and  Australia.  There  is  a  black  coral 
dredged  in  the  Persian  Gulf.  The  African  fisheries  have  changed  hands 
several  times  but  are  now  under  French  control,  so  that  non-French 
dredgers  have  to  pay  a  heavy  royalty.  Previous  to  the  French 
Revolution,  Marseilles  was  the  chief  centre  for  collecting  and  work- 
ing the  coral;  now  Naples,  Genoa  and  Rome  are  the  chief  centres. 


FIG.   12. — A  small  atol.     A  sketch  of  Whitsunday  Island  in  the  South   Pacific- 
(From  Hegner,  College  Zoology,  after  Sedgwick  and  Darwin.) 

The  Algerian  reefs  are  divided  into  10  regions,  only  one  of  which  is 
dredged  each  year,  10  years  being  considered  time  enough  to  allow  the 
beds  to  recuperate.  They  are  dredged  in  waters  from  25  to  1000  feet, 
though  mostly  in  the  shallower  depths. 

The  value  varies  according  to  color,  size  and  current  demand, 
the  last  fluctuating  greatly  with  the  changes  of  fashion.  The  finest 
tints  may  bring  $400  to  $600  per  ounce.  Ordinary  reds  in  small 
pieces,  $10  per  ounce.  Fine  pieces  called  "  collette, "  used  for  children's 
necklaces,  etc.,  bring  $i  per  ounce.  Very  large  pieces  are  much  in 
demand  in  China  for  the  official  buttons  of  the  mandarins. 


CHAPTER  IV 
ECHINODERMATA 

This  phylum  consists  of  a  number  of  well-known  forms  all  of  which 
are  marine  and  most  of  which  are  very  slow  in  their  motions.  As  their 
name  indicates  they  are  the  "spiny-skinned"  animals,  though  the 
spininess  varies  greatly  in  different  species.  They  are  radially  sym- 
metrical and  were,  therefore,  by  earlier  writers  classed  with  the 
Coelenterates  as  "Radiata."  Their  radiate  structure  is  usually  built 
on  a  plan  of  five,  and  their  organs  of  locomotion,  in  most  cases,  consist 
of  small  sucker-like  tube  feet,  controlled  by  a  characteristic  system 
of  water  tubes  known  as  the  water-vascular  system.  Unlike  the 
ccelenterates  they  have  a  well-developed  coelom  and  possess  the  three 
cell  layers  characteristic  of  the  higher  animals.  An  anus,  distinct 
from  the  mouth,  is  generally  present. 

There  are  many  extinct  groups  of  echinoderms  that,  as  fossils,  are 
interesting  and  important  geologically. 

The  living  representatives  of  this  phylum  are  usually  divided  into 
five  classes,  three  of  which  are  of  some,  though  not  of  very  great, 
economic  importance,  the  other  two  classes  are  of  scientific  interest 
only. 

I.  Asteroidea,  Fig.   13.     As  their  name  indicates  these  are  the 
starfishes,  the  most  familiar  of  the  echinoderms.     They  are  typically 
five-rayed,  the  rays  meeting  in  an  indefinite  central  disk.     On  the 
upper  or  aboral  side  is  a  generally  distinct  madreporic  plate,  on  the 
lower  or  oral  side  is  seen  the  centrally  located  mouth,  radiating  from 
which  are  the  five  ambulacral  grooves,  filled  with  tube  feet. 

II.  Echinoidea,   Fig.   14,  the  sea  urchins.     The  pentanerous  ar- 
rangement is  not  so  obvious  here  as  in  the  preceding  class  since  there 
are  no  radiating  arms.    The  calcareous  plates  are  united  into  a  more 
or  less  globular  shell  or  test,  Fig.  15,  covered  with  movable  spines 
(hence  the  name,  hedgehog),  and  perforated  with  five  radiating  sets 
of  holes  for  exit  of  the  long,  slender  tube  feet.     The  plates  that  bear. 

20 


ECHINODERMATA 


21 


the  perforations  form  the  ambulacra!  areas,  the  plates  between  these 
five  areas  form  the  interambulacral  areas.  The  mouth  is  in  the  centre 
of  a  membranous  peristome  and  is  usually  provided  with  a  complicated 
jaw  apparatus  known  as  Aristotle's  lantern. 

III.  Holothuroidea,    Fig.    16,    sea    cucumbers.     As  the   popular 
name  indicates  these  animals,  especially  certain  species,  are  distinctly 


FIG.  13. — Starfish.      xK- 

cucumber-like,  having  an  elongated,  spindle  form,  'with  the  anus 
at  one  end  and  the  mouth,  surrounded  by  branching  ^tentacles  at  the 
other.  The  bony  skeleton  here  consists  of  small  variously  shaped 
plates,  usually  in  such  small  quantity  that  the  body  wall  has  a  soft 
leathery  texture. 


22 


ECONOMIC   ZOOLOGY 


IV.  Ophiuroidea,  Fig.  17.  These  are  the  brittle-stars  or  serpent- 
stars;  the  first  name  is  appropriate  because  of  the  brittle,  delicate 
character  of  the  rays;  the  latter  name  comes,  as  the  class  name  indicates, 
from  the  snake-like  character  of  the  rays.  The  distinct  central  disk 
and  snake-like  arms  are  sufficient  to  identify  the  members  of  the  class, 
Fig.  17.  In  some  species  the  rays  are  much  branched,  making  the 


FIG.   14. — Sea-urchin.      xM- 

animal  very  complex  in  appearance,  as  in  the  basket  fish  or  Venus' 
basket. 

V.  Crinoidea,  Fig.  18.  These  are  the  feather-stars,  sea-lilies,  or 
stone-lilies,  named  from  their  feather  or  plant-like  appearance.  They 
have  five  arms  which  often  branch  repeatedly  and  give  the  feathery 
appearance.  They  are  generally  attached  by  the  aboral  apex,  either 
during  their  developmental  stages  or  throughout  life,  sometimes  by  a 


ECHINODERMATA 


FIG.  15. — Test  of  sea-urchin,  with  spines  removed.      XL 


A  B 

FIG.   16. — A    sea-cucumber,    Thyone  briareus,   partly  buried  in  the  mud. 
(From  Hegner,  College  Zoology,  after  Pearse.) 


ECONOMIC   ZOOLOGY 


long  flexible  stem,  made  up  of  disk-like  segments.  They  occur  at  all, 
though  mostly  moderate,  depths;  many  are  known  only  as  fossils, 
their  calcareous  skeletons  helping  to  form  extensive  limestone  deposits. 
The  Asteroidea  are  of  very  considerable  negative  importance 
since  they  are  a  serious  menace  to  the  shellfish  industry,  especially 
to  oysters.  A  single  starfish,  in  captivity,  is  said  to  have  eaten  20 
clams  in  six  days,  and  since  along  the  northern  coasts  the  starfish 
are  often  extremely  abundant,  they  sometimes  are  very  destructive  to 


FIG.   17. — Serpent  or  brittle-star.      Xi. 

oyster  beds.  The  method  of  getting  rid  of  them  will  be  discussed 
under  the  head  of  oyster  culture. 

The  Echinoidea,  under  the  name  of  sea-eggs,  are  of  some,  though 
not  very  great,  economic  importance.  In  the  West  Indies,  Italy 
and  in  the  far  east  they  are  largely  eaten,  both  raw  and  cooked, 
especially  when  they  are  sexually  mature  and  full  of  eggs,  as  it  is  the 
eggs  that  are  eaten.  A  large  sea-urchin  just  before  spawning  contains 
a  very  considerable  quantity  of  roe.  A  decade  or  more  ago  at  Barbados, 
the  centre  of  the  sea-egg  industry,  the  annual  business  was  worth 
about  $20,000. 

The  Holothurians  are  the  most  important,  economically,  of  the 


ECHINODERMATA  25 

echinoderms.  Several  dozen  species  are  used  as  food,  especially 
by  the  Chinese,  and  other  orientals,  under  the  name  trepang;  they  are 
also  called  b$che-de-mer.  Some  species  bring  very  high  prices,  others 
seem  less  desirable. 

The  animals,  some  of  which  may  reach  a  length  of  two  feet,  are 
eviscerated,  the  leathery  walls  are  then  boiled,  soaked  in  fresh  water, 
smoked,  and  dried.  The  result  is  an  irregular  mass  of  rubber-like 
substance  which  can  be  transported  easily  and  is  made  into  soup  and 
other  articles  of  diet,  which  are  said  to  be  very  palatable. 


FIG.  1 8. — A  crinoid,  Pentacrinus  madearanus.  Xi.  Only  a  part  of  the 
stem  shown.  (From  Hegner,  College  Zoology,  after  Cambridge  Natural  History, 
from  Thompson.) 

Trepang  is  prepared  by  the  Chinese  of  California  and  Hawaii, 
but  the  chief  centres  are  in  the  Orient;  for  example  600  tons  annu- 
ally are  collected  from  the  north  coast  of  Australia,  and  the  annual 
trade  amounts  to  hundreds  of  thousands  of  dollars.  Considerable 
quantities  are  also  collected  in  the  West  Indies. 

The  Ophiuroidea  have  practically  no  economic  importance  and 
the  same  is  true  for  the  Crinoidea  except  for  their  aid  in  forming  lime- 
stone beds  and  in  enabling  geologists  to  determine  geological  horizons. 


CHAPTER  V 
PLATYHELMINTHES.    FLAT-WORMS 

In  older  texts  the  group  name  "Vermes"  was  used  to  include  all  of 
the  worms.  In  modern  books  the  worms  are  usually  placed  in  three  or 
more  phyla — the  Platyhelminthes  or  flat-worms,  the  Nemathelminthes 
or  round- worms,  the  Annulata  or  segmented- worms;  and  sometimes 
the  curious  little  worm-like  rotifers  are  placed  in  a  phylum  of  their 
own,  though  they  and  some  other  worms  are  of  uncertain  affinities. 
The  first  three  of  these  groups  will  be  taken  up  in  order,  as  each  has 
considerable  economic  importance. 

The  flat-worms,  though  a  lowly  group,  are  more  highly  specialized 
than  the  ccelenterates.  They  have  three  .germ  layers,  the  mesoderm 

forming  important  systems  of 
organs — muscles,  urogenital  organs, 
etc.  They  are  bilaterally  instead 
of  radially  symmetrical  and,  as  the 

FIG.   i9.-Planaria.     A  common  name   indicates     are   of  a  distinctly 

fresh- water  flat-worm.      X5-  J 

flattened     form.       Their     internal 

structures  are  difficult  to  make  out  in  the  laboratory,  and  vary  con- 
siderably in  different  species,  being  highly  degenerate  in  some  parasitic 
forms. 

The  flat- worms  are  usually  divided  into  the  three  following  classes : 

I.  Turbellaria,  Fig.  19,  free  living  forms  with  ciliated  ectoderm;  found 
in  fresh  and  salt  water,  rarely  on  land.     Represented  by  the  familiar 
genus  Planaria  of  our  ponds  and  pools. 

II.  Cestoda,  Fig.   20,   long,   much   flattened  forms   divided   into 
numerous    (sometimes    many   hundred)    more   or    less   independent 
segments,  no  alimentary  canal  present;  parasitic  in  habits.     Repre- 
sented by  the  common  tapeworms. 

III.  Trematoda,    Fig.    21,   usually  short    and   broadly  flattened, 
with  ventral  suckers  and  much  branched  digestive  and  reproductive 
organs.     Parasitic  in  habits.     Represented  by  the  liver  and  other 

flukes. 

26 


PLATYHELMINTHES.      FLAT-WORMS  27 

Since  the  Turbellaria  have  little  if  any  economic  importance  they 
will  not  be  further  discussed. 

The  Cestodes  or  tapeworms,  Fig.  20,  are  found  in  the  digestive 
tracts  of  vertebrates.  Naturally  those  found  in  man  are  of  the  most 
interest  and  importance.  There  are  at  least  two  large  tapeworms 
parasitic  in  man:  Tania  saginata,  the  unarmed,  beef,  or  fat  tapeworm, 
the  commonest  form,  and  T.  solium  or  pork  tapeworm.  The  former 
is  taken  into  the  body  by  eating  imperfectly  cooked  beef;  the  latter 
by  eating  imperfectly  cooked  pork.  The  latter  is  the  more  dangerous 
but,  according  to  Osier,  is  very  rare  in  the  U.  S.  The  former  is  found 
practically  everywhere  and  though  unpleasant  is  not  necessarily  very 
serious. 

The  life-history  of  T.  saginata  is  briefly  as  follows:  the  adult  worm 
lives  in  the  intestine  of  man;  usually  only  one  worm  is  found  in  an 
individual,  but  as  many  as  59  have  been  reported.  The  worm  has 
a  small  head,  about  2  mm.  in  diameter,  Fig.  20,  B,  with  four  suckers 
but  without  the  circle  of  hooks  that  is  found  in  T.  solium  and  that  is 
shown  in  the  figure.  Following  the  head  or  scolex  is  a  slender  neck, 
the  segments  of  which  gradually  enlarge  toward  the  posterior  end 
until,  in  the  main  body  of  the  animal,  they  may  be  i  cm.  wide  and  2 
or  3  cm.  long.  There  may  be  1000  or  more  segments  or  proglottids 
in  a  large  worm,  totaling  a  length  of  20  or  30  feet.  Each  of  the  pos- 
terior segments  is  a  complete  animal  sexually,  and  they  are  con- 
stantly breaking  off  and  passing  to  the  exterior  with  the  feces. 

In  ridding  a  patient  of  tapeworm  by  the  use  of  purgatives  it  is 
necessary  to  cause  the  extrusion  of  the  entire  worm,  for  if  the  scolex 
remain  attached  to  the  intestine  the  segments  will  be  rapidly  re- 
generated, at  the  rate,  perhaps,  of  a  dozen  a  day,  so  that  the  worm 
will  soon  regain  its  normal  size. 

It  is  estimated  that  a  single  worm  may  produce  150,000,000  eggs 
per  year;  these,  together  with  entire  proglottids,  are  passed  to  the 
exterior  and  may  be  taken  into  the  digestive  tract  of  a  beef  with 
grass  or  in  drinking  water.  While  still  in  the  proglottids  the  eggs 
are  fertilized  and  develop  into  tiny  embryos.  These  embryos  if  taken 
into  the  intestine  of  a  beef  burst  out  of  their  containing  shells,  bur- 
row through  the  digestive  walls  of  their  second  host  and  become 
encysted,  as  tiny  bladder-shaped  worms  known  as  cysticerci,  or 
bladder  worms,  in  the  muscles,  especially  in  the  tongue  and  chewing 


28 


ECONOMIC   ZOOLOGY 


muscles.  If,  now,  this  muscular  tissue  be  eaten,  imperfectly  cooked, 
by  man,  the  cysticerci,  when  the  meat  is  digested  complete  their 
development  into  the  adult  T.  saginata  in  the  intestine  of  the  new 
victim. 

Taenia  is  most  common  in  women  especially  between  20  to  40 
years,  and  a  worm  may  live  for  years,  if  not  expelled  by  proper 
treatment.  Of  course,  if  no  raw  or  very  rare  beef  be  eaten  it  is  im- 
possible to  be  infected;  probably  most  infections  come  from  pri- 
vately killed  cattle,  as  the  larger  slaughter  houses  keep  the  beef  in  cold 


FIG.  20. — Human  tapeworm,  Tcenia  solium.  A,  the  entire  animal.  X  /4- 
B,  the  head  or  scolex,  sc,  enlarged;  n,  neck  region;  p,  segment  or  proglottid;  s,  suckers; 
sc,  scolex;  gp,  genital  pore;  h,  hooks. 


storage   for   three   weeks,    which  is  thought  to  destroy  the  cysticerci 
that  may  be  present.     Thorough  salting  will  also  kill  the  cysticerci. 

The  life-history  of  T.  solium,  which  most  books  describe  as  the 
"common"  tapeworm,  is  essentially  the  same  as  that  of  T.  saginata 
except  that  the  hog  is  the  second  host.  The  head  here  is  very  tiny, 
not  so  large  as  the  head  of  a  pin,  and  is  armed  with  hooks,  hence  the 
name  "armed"  tape  worm.  The  cysticercus  of  T.  solium  is  not  so 
easily  killed  by  cold  storage  as  that  of  T.  saginata,  so  that  there  is 
always  danger  from  eating  raw  pork,  though  the  greatest  danger  is 
from  another  worm,  to  be  described  later. 


PLATYHELMINTHES.      FLAT-WORMS 


T.  solium  is  a  more  dangerous  parasite  from  the  possibility  of  the 
occurrence  of  cysticerci  in  man,  forming  vesicles  known  as  hydatids, 
which  may  cause  death.  These  hydatids  are  embryos  that,  in  certain 
cases,  develop  in  the  intestine  where  they  were  born  and  then  migrate 
into  the  muscles  of  the  first  host. 

The  Trematodes,  Fig.  21,  are  represented  by  the  liver,  lung, 
intestinal  and  venal  flukes  of  man  and  other  animals,  the  disease 
being  known,  in  a  general  way  as  Distomiasis,  from  Distoma,  the 
generic  name  of  the  common  flukes.  According  to  Osier  there  are 
six  species  of  liver  flukes  known  in  man.  One  of  these  is  extremely 
common  in  some  parts  of  the  Orient  and  has  occasionally  been  found 
in  the  United  States.  The  patient  may  die  after  many  years  of  illness. 
One  of  the  commonest  of  the  flukes  is  Distomum 
hepaticum,  living  in  the  bile  ducts  of  sheep  and  other 
herbivorous  animals.  It  is  found  the  world  over  and 
sometimes  causes  severe  loss  among  flocks  from  liver 
rot. 

Since  a  single  fluke  is  said  to  produce  500,000  eggs 
and  since  there  may  be  200  adult  flukes  in  a  single 
sheep,  it  would  seem  that  the  disease  should  be  ex- 
tremely common,  but  the  life-history,  as  will  be 
presently  seen,  is  so  complicated  that  the  mortality 
is  enormous  and  but  few  eggs  ever  produce  adult 
flukes. 

The  life-history  of  the  sheep  fluke  is,  briefly, 
as  follows:  The  fertilized  egg  is  deposited  by  the  •  *•  genit^!  pore; 

J  m,  mouth;  s,  ven- 

hermaphroditic  adult  in  the  bile  ducts  of  the  sheep,  trai  suckers, 
whence  it  passes  to  the  intestine  and  thence  to  the 
exterior  with  the  excrement.  If  the  ovum  chance  to  get  into  water  at 
the  right  temperature  it  develops  into  a  ciliated  larva  known  as  a 
miracidium.  In  swimming  about,  if  this  larva  come  in  contact,  within 
a  few  hours,  with  a  fresh  water  snail  of  a  certain  species  it  burrows 
into  the  soft  tissue  of  the  mollusc  where,  in  about  two  weeks,  it  develops 
into  the  next  stage,  the  sac-like  sporocyst.  The  sporocyst  gives  rise 
to  several  redia,  of  which  there  may  be  one  or  more  generations, 
the  final  generation  becoming  the  tailed  cercaria.  The  cercaria  leaves 
the  body  of  the  snail  and  after  swimming  about  for  a  time  forms  a 
cyst  on  a  blade  of  grass.  If  this  blade  of  grass  be  eaten  by  a  sheep 


FIG.  21. — Liver 
fluke,  Fasciola 
hepatica.  Xi. 


30  ECONOMIC   ZOOLOGY 

the  larva  escapes  from  the  cyst,  makes  its  way  from  the  intestine  into 
the  bile  ducts  where  it  assumes  the  adult  condition.  It  will  be  seen 
that  the  chances  for  an  egg  to  meet  all  of  these  unusual  conditions 
are  very  slight;  hence  the  enormous  number  of  eggs  produced  by  each 
adult  fluke. 


CHAPTER  VI 
NEMATHELMINTHES.    ROUND-WORMS 

These  are  the  round  or  thread-worms,  which  are  characterized 
by  their  long,  slender,  cylindrical  bodies  that  are  entirely  devoid  of 
internal  or  external  segmentation.  Their  internal  structure  is  usually 
moderately  simple,  as  might,  perhaps,  be  expected  of  a  group,  many 
members  of  which  are  parasitic.  Some  of  them  are  of  microscopic 
size;  others  reach  a  length  of  a  meter.  Their  chief  if  not  only  claim 
to  economic  importance  lies  in  their  parasitic  habits. 


FIG.  22. — Parts  of  Ascaris  lumbricoides.  a,-b,  and  c,  enlarged;  d,  highly  magnified 
a,  posterior  end  of  a  male  with  two  penial  setae  (Sp);  b,  anterior  end  from  the 
dorsal  side,  showing  the  dorsal  lip  with  its  two  papillae;  c,  the  same  from  the  ventral 
side  with  the  two  lateral  ventral  lips  and  the  excretory  pore  (P) ;  d,  egg  with  external 
membrane  of  small  clear  spherules.  (From  Hegner,  College  Zoology,  after  Sedgwick, 
from  Leuckart.) 

One  of  the  larger  and  more  common  of  the  round-worms  is  the 
genus  Ascaris,  Figs.  22,  23  and  24,  found  as  a  parasite  in  the  intestine 
of  man,  horses  and  pigs.  It  is  a  brownish  worm,  about  6  mm.  in 
diameter  and  from  12  to  30  cm.  long,  the  female  being  usually  some- 
what the  larger;  the  main  features  of  its  anatomy  are  illustrated  by  the 
accompanying  figures.  The  species  common  to  man  is  A.  lumbricoides, 
the  human  eel  worm.  It  is  one  of  the  most  common  of  the  human 
worm  parasites,  being  frequently  found  in  children  from  5  to  10 
years  of  age,  and  in  women  more  often  than  in  men.  It  is  also 
more  common  in  warm  than  in  cold  climates,  and  is  more  frequently 

31 


32 


ECONOMIC   ZOOLOGY 


met  with  in  the  country  (where  sewage  disposal  is  often  crude)  than 
in  cities.  There  are  usually  from  one  to  half  a  dozen  worms  in  one 
patient,  but  as  many  as  600  in  one  person  have  been  reported. 
They  may  merely  cause  diarrhea  and  other  discomforts  or  they  may 
be  fatal.  The  condition  may  be  identified  by  finding  the  worms  or 
their  eggs  in  the  patients'  stools.  The  history  is  simple,  no  second 
host  being  necessary.  The  eggs  that  are  passed  out  of  the  body  in  the 
feces  may  be  taken  into  the  digestive  tract  of  the  same  or  of  another 
person  in  drinking  water,  upon  unwashed  fruits,  vegetables  or  salads, 


talk 


esc. 


ovt 


v.v 


tct 

FIG.  23. — Transverse  section  of  Ascaris  lumbricoides.  X 15  cu,  cuticle; 
dl,  dorsal  line,  der.  epthm,  epidermis;  ex.v,  excretory  tube;  int,  intestine;  lot.  I,  lateral 
line;  m,  muscular  layer;  ovy,  ovary;  ut,  uterus;  v.v.t  ventral  line.  (From  Hegner, 
College  Zoology,  after  Parker  and  Haswell,  from  Vogt  and  Yung.) 

or  by  simply  eating  with  dirty  hands;  possibly  the  eggs  may  be  carried 
to  man's  food  or  water  by  flies.  It  is  thus  easy  to  understand  how 
young  children  may  be  infected  and  why  women,  who  generally  handle 
the  raw  fruits  and  vegetables,  are  more  subject  to  the  disease  than  men. 
Also  how  bad  sewage  may  spread  the  eggs.  After  entrance  into  the 
body  it  takes  from  one  to  several  months  for  the  eggs  to  develop  into 
the  adult  worms. 

Santonin  and  calomel  are  the  usual  drugs  used  to  rid  the  intestine 
of  the  eel  worm. 


NEMATHELMINTHES.      ROUND- WORMS 


33 


Hookworm. — Probably  the  most  widespread 
and  important  worm  parasite  of  man  is  the 
now  popularly  known  hookworm,  of  which  there 
are  two  chief  forms,  the  European,  Ankylostoma 
duodenale,  and  the  American,  Necator  ameri- 
canus.  The  disease  caused  by  this  worm  is 
generally  known  as  hookworm  disease,  or  tech- 
nically as  uncinariasis  or  ankylostomiasis. 

The  parasites  occur  in  most  parts  of  the 
world  and  practically  all  tropical  countries  show 
the  presence  of  the  disease,  often  in  a  large  per- 
centage of  the  population;  for  example  90  per 
cent,  of  the  people  of  Porto  Rico  formerly  were 
infected.  While  typical  of  the  tropics,  the  dis- 
ease is  often  common  in  the  temperate  zones.  / 
In  the  southern  states  of  the  Union  the  disease 
is  very  prevalent;  especially  among  the  poorer 4<__M 
classes.  The  disease  has  tbeen  recognized  in 
tropical  countries  for  three  centuries,  though  its 
cause  was  not  discovered  until  past  the  middle 
of  the  nineteenth  century.  The  first  case  in 
the  United  States  was  reported  in  Philadelphia 
in  1893. 

Those  who  live,  or  have  travelled  in  the 
southern  states  are  familiar  with  the  so-called 
"poor  whites"  of  that  region.  It  has  been 
estimated  that,  at  least  until  a  few  years  ago, 
there  were  some  2,000,000  of  these  unfortunates. 
They  were  formerly  considered  to  be  a  sort  of 
degenerate  race,  too  lazy  or  stupid  or  both  to 
work,  who  eked  out  a  miserable  existence  on 
their  pitiful  little  plantations.  These  people 
are  pale  and  anaemic  and  often  thin  to  emacia- 
tion; the  children  are  stunted  physically  and 


FIG.  24. — A  female  Ascaris  lumbricoides  cut  open  to 
show  internal  structures.  x%.  I,  pharynx;  2,  intes- 
tine; 3,  ovary;'  4,  uterus;  5,  vagina;  6,  genital  pore;  7, 
excretory  tube;  8,  excretory  pore.  (From  Hegner,  College 
Zoology,  after  Shipley  and  MacBride.) 
3 


34 


ECONOMIC   ZOOLOGY 


deficient  mentally;  many  are  tuberculous.  One  of  the  curious  and 
disgusting  characteristics  of  these  people,  at  times,  is  the  habit  of 
eating  dirt,  wood,  hair,  clothing,  etc.,  although  the  victim  usually  will 
deny  the  habit. 

About  the  beginning  of  the  present  century  Dr.  C.  W.  Stiles, 
a  zoologist,  then  in  the  Bureau  of  Animal  Industry,  now  in  the  Marine 
Hospital  Service,  knowing  the  effect  of  hookworm  upon  the  lower 
animals,  made  the  prediction  that  it  would  be  found  that  the  condition 
of  these  supposedly  lazy  "poor  whites"  of  the  south  was  due  to  their 
being  infected  with  hookworm.  The  newspapers  made  great  sport 
of  Dr.  Stiles'  "lazy  germ"  but  the  prediction  was  very  soon  fulfilled, 


FIG.  25. — Hookworm,    Necator    americanus.    A,   male;    B,   female.     Xio.     (After 
V.  L.  Kellogg  and  Doane,  Economic  Zoology  and  Entomology,  from  Wilder.) 

and  we  now  know  that  these  "poor  whites"  are  not  degenerates 
but  are  sufferers  from  a  serious,  though  usually  easily  cured,  disease, 
named  from  the  worm  that  is  its  cause. 

The  worm,  Fig.  25,  is  a  small  nematode  about  i  cm.  in  length  and 
about  the  diameter  and  color  of  a  very  dirty  piece  of  sewing  cotton. 
The  male  may  be  easily  distinguished  from  the  female  by  the  flaring, 
fin-like  posterior  extremity.  At  the  anterior  end  is  the  tiny  mouth, 
armed  with  sharp  teeth  for  puncturing  the  soft  mucosa  of  the  digestive 
tract;  it  is  in  the  jejunum  that  they  are  chiefly  found.  They  vary  in 
number,  in  a  single  individual,  from  about  a  dozen  to  over  4000; 
but  the  severity  of  the  attack  is  not  always  in  proportion  to  the 
number  of  worms  found,  death  having  resulted  with  the  former 
number  of  worms  and  recovery  with  a  latter  number.  They  may  live 
in  the  intestine  for  five  or  six  years,  or  even  longer.  The  complete 


NEMATHELMINTHES.      ROUND-WORMS  35 

life  cycle  of  the  worm  cannot  take  place  in  the  single  person,  so  that 
the  number  of  worms  in  the  intestine  can  be  increased  only  by  a  new 
infection. 

The  female  worm  produces  the  eggs,  which  are  about  35X70  micra 
(Kooo  mm.)  in  size,  in  enormous  numbers  and  they  pass  to  the  ex- 
terior with  the  feces,  as  many  as  4,000,000  it  is  estimated,  with  one  stool. 
Desiccation,  direct  sunlight,  too  much  water  and,  generally,  freezing 
will  kill  these  eggs,  which  have  usually  begun  to  segment  when  passed 
out  with  the  stool. 

The  rapidity  of  development  depends  upon  the  temperature  and 
moisture,  but  the  larvae  become  infective  in  four  or  five  days;  under 
favorable  conditions  these  larvae  may  live  for  months. 

Infection  may  take  place  either  by  the  mouth  or,  more  commonly, 
through  the  skin.  It  is  the  entrance  of  the  tiny  larvae  through  the  skin, 
more  often  of  the  feet,  but  of  any  part  of  the  body,  that  causes  the  ir- 
ritation known  as  " ground  itch,"  "foot  itch,"  "dew  itch,"  etc.  A 
large  percentage  of  hookworm  disease  histories  show  cases  of  ground 
itch.  The  mode  of  entry  through  the  skin  was  discovered  in  1898 
by  Looss  in  a  very  interesting  way.  While  experimenting  with  hook- 
worm larvae  he  spilled  some  of  them  on  his  hand;  he  noticed  a  burning 
sensation  and  in  a  few  minutes  the  larvae  had  disappeared.  After  the 
proper  interval,  about  two  months,  he  found  himself  suffering  with 
the  hookworm  disease.  To  determine  what  had  become  of  the  larvae 
that  were  spilled  on  his  hand  he  poured  some  larvae  on  the  leg  that 
was  about  to  be  amputated  from  a  boy;  on  sectioning  the  skin  of 
this  leg,  after  amputation,  he  found  the  larvae  had  worked  their  way 
through  the  skin  by  way  of  the  hair  follicles,  sweat  ducts,  etc.  To 
follow  the  further  course  of  the  larvae  he  placed  some  of  them  on 
the  skin  of  a  number  of  dogs  which  were  killed  and  examined  at 
various  intervals.  In  this  way  he  worked  out  the  entire  course  of  the 
larvae  from  the  skin  to  their  final  resting  place  in  the  intestine,  which 
is"as  follows:  after  passing  through  the  skin  they  enter  the  subcu- 
taneous blood  vessels  and  are  carried  by  the  blood  current  to  the  heart; 
thence  to  the  lung  capillaries,  from  which  they  burrow  through  the 
tissues  into  the  lung  alveoli,  thence  they  work  their  way  up  the  trachea 
to'the  oesophagus,  down  which  they  pass  to  the  stomach  and  intes- 
tine. It  is  the  tiny  lesions  made  by  the  larvae  in  passing  through 


36  ECONOMIC   ZOOLOGY 

the  lung  tissue  that  cause  the  patient  to  be  unusually  susceptible  to 
tuberculosis. 

The  question  will  be  asked — "How  can  a  comparatively  small 
number  of  tiny  worms  cause  such  a  marked  anaemia  in  a  full  grown 
human  being?"  The  worms  cause  their  serious  effects  in  two  or  three 
ways.  The  amount  of  blood  actually  consumed  by  them  is,  perhaps 
not  very  serious,  but  it  is  supposed  that  they  secrete  a  substance  from 
glands  in  the  head  that  prevent  clotting  of  the  blood,  so  that  as  they 
move  from  place  to  place  in  the  intestine  the  tiny  wounds  they  leave 
continue  to  bleed  for  some  time.  Again  it  is  stated  by  some,  that 
another  substance  is  secreted  by  the  worm  that  prevents  the  formation 
of  new  corpuscles  to  replace  those  that  are  lost.  If  both  of  these 
substances  were  at  work  at  the  same  time  the  results  might  be  most 
serious.  Still  another  result  of  their  work  is  seen  in  the  numerous  small 
sores  or  ulcers  left  in  the  mucosa  of  the  intestine  by  the  bites  of  the 
worms.  These  lesions  give  many  possible  points  of  bacterial  infection. 

One  hopeful  aspect  of  the  disease  is  the  usually  easy  cure,  by  the  use 
of  two  cheap  drugs,  Thymol  and  Epsom  Salts.  They  should  not  be 
taken  without  the  advice  of  a  physician,  and  should  not  be  used  along 
with  alcohol  nor  any  sort  of  oil,  as  the  results  might  be  very  serious  or 
even  fatal. 

It  is,  of  course,  chiefly  through  soil  pollution  that  the  disease  is 
spread.  Negroes  in  the  south  are  almost  all  infected  with  hookworm, 
but  for  some  reason,  probably  from  having  been  infected  through 
long  generations  in  Africa,  they  are  not  seriously  affected  by  the  parasite 
and  hence  are  not  apt  to  subject  themselves  to  treatment.  As  they 
are  notoriously  indifferent  to  sanitary  laws,  they  probably  are  the  chief 
instruments  in  the  spread  of  the  disease  and  are  the  greatest  problem 
in  its  attempted  control.  The  Rockefeller  Hookworm  Commission  is 
endeavoring  by  a  campaign  of  education  and  wholesale  medical  treat- 
ment to  eradicate  this  curse  of  the  south,  which  if  accomplished  will 
go  far  toward  solving  many  of  the  economic  problems  of  that  region. 
What  treatment  and  sanitation  can  accomplish  is  shown  by  the 
change  in  conditions  in  the  great  Bilibid  prison  in  Manila,  P.  I.  "  When 
the  Americans  took  charge  of  Bilibid  prison  the  death  rate  was  238 
per  1000  per  year;  by  improving  the  sanitary  conditions  this  death 
rate  was  reduced  to  about  75  per  1000;  here  it  remained  stationary 
until  it  was  discovered  that  a  very  high  percentage  of  the  prisoners 


NEMATHELMINTHES.      ROUND-WORMS  37 

were  infected  with  hookworms  and  other  intestinal  parasites;  then  a 
systematic  campaign  was  inaugurated  to  expel  these  worms,  and  when 
this  was  done  the  death  rate  fell  to  13.5  per  1000." 

Trichinella  (Trichina)  spiralis,  Fig.  26,  is  a  small  nematode  the 
adult  male  of  which  is  about  1.5  mm.  in  length  and  a  female  %  mm. 
Both  sexes  are  enlarged  somewhat  toward  the  posterior  end,  where, 
in  the  male,  are  two  short,  conical  protuberances. 

The  adults  are  found  in  the  intestine  of  man  and  other  animals. 
The  female  worm  produces  a  large  number  of  embryos,  perhaps  10,000 
or  more,  which  immediately  begin  to  migrate  into  the  surrounding 
tissues,  finally  finding  their  way,  perhaps  through  the  blood  and  lymph 
streams,  to  the  muscles  of  their  host  where  they  grow  until  nearly 
i  mm.  in  length.  As  it  grows  the  embryo  coils  itself  into  a  spiral, 


FIG.  26. — Trichinella   spiralis   encysted  among  muscle  fibres.     Highly  magnified. 
(From  Hegner,  College  Zoology,  after  Shipley  and  MacBride,  from  Leuckart.) 

and  forms  an  elliptical  cyst  around  itself  as  it  lies  in  the  connective 
tissue  between  the  voluntary  muscle  fibres.  It  has  been  estimated 
that  there  were  from  5,000,000  to  100,000,000,  cysts  in  the  bodies  of 
persons  who  have  died  of  the  disease.  This  cyst,  after  seven  or  eight 
months,  begins  to  degenerate  and  becomes  calcified,  and  the  worm  is  de- 
stroyed, though  it  may  take  from  2  to  10  years.  The  adults  get  into 
the  human  intestine  from  eating  uncooked  pork  in  which  there  are  cysts. 
The  cysts  dissolve  in  our  intestine,  thus  liberating  the  worms  which  in 
five  or  six  days  are  able  to  produce  embryos,  and  this  they  may  continue 
to  do  for  a  month,  if  the  adults  are  not  gotten  rid  of  by  purgatives 
or  by  diarrhea;  in  any  case  the  adult  worms  usually  disappear  in  five 
or  six  weeks.  Just  how  the  hog  becomes  infected  is  uncertain,  probably 
by  eating  infected  offal,  or  infected  rats;  certainly  the  hog  seldom  has 
the  opportunity  of  eating  human  flesh  with  or  without  the  trichinella 
cysts. 

If  the  disease,  Trichiniasis,  be  recognized  before  the  embryos  have 


3  ECONOMIC   ZOOLOGY 

begun  to  migrate  it  may  be  arrested  by  use  of  calomel  and  other 
purgatives,  but  after  the  worms  are  in  the  muscles  there  is  no  treatment 
that  will  affect  them. 

The  death-rate  has  varied  in  different  outbreaks  from  i  to  30  per 
cent.  In  America  the  disease  is  comparatively  rare  and  is  largely  con- 
fined to  foreign-born  people  who  make  a  practice  of  eating  raw  ham, 
sausage,  etc.  In  certain  German  States  where  this  practice  is  very 
common  the  disease  is  proportionately  more  prevalent.  As  a  sure 
preventive  it  is  simply  necessary  to  thoroughly  cook  all  pork.  It  is 
said  that  the  centre  of  a  large  piece  of  fairly  well  cqoked  pork  may  con- 
tain live  cysts  and  that  salting  does  not  always  kill  them.  Pork  from 
private  slaughter  houses  is  more  apt  to  be  infected.  The  fact  that  pork 
is  marked  "U.  S.  Inspected"  does  not  guarantee  it  to  be  free  from 
trichinella. 

Filaria  is  a  genus  of  small  (less  than  i  mm.)  round-worms  causing, 
in  man,  various  diseases.  One  curious  fact  about  certain  species  is 
that  they  are  found  in  the  human  blood  at  night  but  not  during  the 
day,  or  at  least  in  very  much  smaller  numbers.  In  a  case  where  a 
patient  reversed  his  habits  and  slept  during  the  day  the  parasites  also 
reversed  their  habits  and  were  found  during  the  day.  How  the 
parasites  enter  the  blood  is  not  certain,  probably  by  the  bite  of 
a  mosquito,  possibly  through  drinking  water.  It  is  often  very  common 
in  the  tropics.  One  of  the  diseases  probably  due,  at  least  in  some  cases, 
to  this  parasite  is  elephantiasis,  which  causes  enormous  and  incurable 
enlargements  of  the  limbs  and  other  parts  of  the  body.  There  seems 
to  be  no  drug  that  will  destroy  this  parasite  in  the  blood. 

Guinea-worm  (Dracunculus)  is  one  of  the  largest  of  the  round- 
worms,  reaching  a  length  of  nearly  a  meter.  The  larvae  live  in  a  water 
flea,  Cyclops,  and  probably  gain  access  to  the  human  digestive  tract 
in  drinking  water.  Here  they  mature  and  the  male  dies  and  is  voided. 
The  female,  after  being  impregnated,  leaves  the  intestine  and  becomes 
fully  developed  in  the  subcutaneous  tissue.  She  contains  large  numbers 
of  embryos  and  to  get  these  to  the  exterior  she  migrates  downward 
into  the  leg,  usually  reaching  the  foot,  where  the  head  punctures  the 
skin,  forming  a  small  vesicle  which  ruptures  and  allows  the  embryos 
to  escape.  The  worm  may  then  leave  the  body  spontaneously  or 
it  may  be  carefully  withdrawn,  care  being  taken  not  to  rupture  it. 
It  is  sometimes  the  custom  to  wind  the  extruded  end  on  a  small  stick 


NEMATHELMINTHES.      ROUND-WORMS  39 

to  prevent  the  worm  from  withdrawing  into  the  body,  each  day  a  little 
more  of  the  worm  is  wound  on  the  stick  until  it  is  all  out  of  the  skin. 
It  may  also  be  removed  by  surgery  or  may  be  killed  by  injections  of 
bichloride  of  mercury. 

Pinworm,  whipworm  and  various  other  small  nematodes  are  some- 
times parasitic  in  the  human  digestive  tract. 


CHAPTER  VII 
ANNULATA,  SEGMENTED  WORMS 

The  Annulata  or  Annelids  are  those  worms  in  which  the  elongated, 
usually  more  or  less  cylindrical,  body  is  externally  divided  into  a 
number  of  rings  representing  the  internal  division  into  a  series  of 
more  or  less  similar  somites  or  metameres.  There  is  usually  an  ex- 
tensive ccelom  and  a  complicated  system  of  blood  vessels.  The  nervous 
system  usually  consists  of  a  dorsally  located  brain  or  cerebral  gan- 
glion in  the  anterior  region,  connected  around  the  digestive  tract  to  a 
ventral  nerve  cord  which  usually  has  a  series  of  ganglia  corresponding 
to  the  somites.  The  excretory  organs  are  paired  nephridia,  which  are 
coiled  tubes,  usually  one  pair  for  each  somite,  connecting  the  ccelom 
with  the  exterior. 

The  annelids  are  variously  classified  by  different  authors;  the  two 
most  important  classes  and  the  only  two  of  serious  economic  importance 
are  the  Chaetopoda,  represented  by  the  earthworms  and  the  Hirudinea 
or  leeches. 

Earthworms. — There  are  some  800  species  of  earthworms,  about  90 
of  which  are  found  in  North  America.  There  are  about  a  dozen  species 
of  the  common  Lumbricus  and  Allolobophora.  There  are  several  from 
South  Africa  and  Australia  that  are  described  as  being  iJ/£  meters  in 
length.  They  are  found  everywhere  except  in  frozen  latitudes  and  al- 
titudes and  in  dry  sandy  regions.  They  generally  burrow  below  frost 
in  winter  though  some  are  said  to  survive  freezing.  According  to  the 
operator  of  a  large  steam-shovel  they  are  sometimes  found  18  or  20 
feet  below  the  surface  of  the  ground. 

They  feed  on  almost  any  kind  of  organic  matter,  a  considerable 
portion  of  which  they  obtain  from  earth  that  is  passed  through  the  body. 
This  earth  from  which  the  food  has  been  extracted  is  deposited  at  night 
around  the  openings  of  their  burrows  as  fine  pellets  known  as  castings. 
The  amount  brought  up  each  night  by  each  worm  is  so  considerable  as  to 

40 


ANNULATA,    SEGMENTED    WORMS  41 

interfere  with  the  course  ,of  the  golf  balls  on  the  putting  greens  of 
golf  courses.  To  rid  these  greens  of  this  annoyance  they  are  sometimes 
sprinkled  with  a  lime-and-sulphur  mixture  or  some  other  poison 
that  is  harmless  to  grass.  As  soon  as  the  liquid  soaks  into  the  ground 
the  worms  begin  to  wriggle  out  of  their  unseen  burrows  so  that  they  may 
be  picked  up  and  destroyed.  To  illustrate  the  abundance  of  earth- 
worms in  the  soil,  the  writer  once  collected,  in  this  way,  over  one  hun- 
dred worms,  big  and  little,  from  a  square  yard  of  green.  This  habit  of 
bringing  the  subsoil  to  the  surface  is  most  important  to  the  growth  of 
vegetation,  the  burrows  make  the  soil  porous,  thus  allowing  air  and  mois- 
ture to  penetrate  the  earth  and  making  it  easier  for  roots  to  work  through 
the  soil,  and  the  castings  are  constantly  building  up  a  finely  divided 
surface  at  the  rate,  according  to  Darwin,  of  about  one-fifth  of  an  inch 
each  year,  so  that  in  a  generation  a  rocky  field  may  have  all  of  its 
stones  buried  out  of  sight.  The  intestinal  secretions  mixed  with  these 
castings  are  probably  beneficial  to  the  soil. 


FIG.  27. — Medicinal  leech,  Hirudo  medicinalis.      X%.     The  larger  sucker  is  at  the 

.     posterior  end. 

Darwin  remarks  upon  the  fact  that  long  before  the  plow  was  in- 
vented, even  in  the  form  of  a  crooked  stick,  the  earthworms  were  con- 
tinually turning  up  the  soil  in  this  way.  Although  they  may  some- 
times do  some  damage  to  young  and  tender  plants,  earthworms  are 
evidently  of  immense  benefit  to  man.  Certain  laboratory  experiments, 
also,  have  shown  them  to  be  of  undoubted  benefit  to  plants. 

It  is  also  said  that  earthworms  may  be  and  actually  are  used  as 
food,  though  they  will  probably  never  be  popular  among  civilized 
peoples.  On  the  other  hand  they  may  occasionally  be  a  source  of 
infection  in  certain  diseases  by  burrowing  in  the  carcasses  of  buried 
animals  and  bringing  the  germs  to  the  surface  where  they  may  infect 
other  animals.  They  are  thought  to  convey  the  germs  of  gapes,  a 
disease  of  chicks  caused  by  a  small  worm  parasite. 


-••8 


.-V-12 


FIG.  270. — Diagram  of  the 
internal  organs  of  the  leech. 
i,  head  with  eye-spots;  2,  mus- 
cular pharynx;  3,  ist  diverti- 
culum  of  crop;  4,  nth  diver- 
ticulum  of  crop;  5,  stomach; 
6,  rectum;  7,  anus;  8,  cerebral 
ganglia;  9,  ventral  nerve  cord; 
10,  nephridium;  n,  lateral 
blood  vessel;  12,  testis;  13,  vas 
deferens;  14,  prostate  gland; 
15,  penis;  16,  ovary;  17,  uterus. 
(From  Hegner,  College  Zoology, 
after  Shipley  and  MacBride.) 


ECONOMIC   ZOOLOGY 

Leeches,  Fig.  27.— The  leeches,  of  which  the 
genus  Hirudo  may  be  taken  as  an  example, 
are  somewhat  flattened  annelids,  with  a  large 
posterior  and  a  smaller  anterior  sucker;  the 
mouth  is  in  the  centre  of  the  latter  and  may 
or  may  not  be  armed  with  jaws  or  teeth. 
Only  the  digestive  system  will  be  noted 
here.  It  consists  of  a  short  pharynx  into 
which  open  certain  glands  whose  secretion 
is  to  keep  the  blood,  on  which  the  animal 
feeds,  from  clotting.  The  pharynx,  Fig. 
270,  2,  opens  into  an  enormous  crop,  3,  4, 
with  about  n  pairs  of  lateral  pouches  for 
the  storage  of  enough  blood  to  last,  perhaps, 
for  many  months,  as  the  leech  may  have 
very  infrequent  opportunities  for  feeding. 
Back  of  the  crop  are  a  small  stomach,  5, 
and  intestine,  6,  opening  to  the  exterior 
through  a  dorsally  located  anus,  7.  The 
leech  is  admirably  adapted  to  its  peculiar 
parasitic  mode  of  life.  Its  suckers  enable 
it  to  quickly  attach  itself  to  a  passing  ani- 
mal, mammal,  turtle,  fish,  etc.,  its  mouth 
enables  it  to  extract  blood  from  its  host 
without  pain  to  the  host,  its  glands  keep 
the  blood  from  clotting,  and  its  huge  crop 
enables  it  to  store  up  a  very  large  quantity 
of  blood  at  each  of  its  probably  infrequent 
feeding  times. 

This  power  of  extracting  a  considerable 
quantity  of  blood,  in  a  painless  manner, 
has  given  the  medicinal  leech,  Hirudo  medi- 
cinalis,  its  value  to  man.  In  the  case  of 
bruises  and  certain  other  pathologic  condi- 
tions it  is  merely  necessary  to  apply  a 
hungry  leech — they  may  be  12  to  15  cm. 
long — to  the  desired  spot  and  it  will  pain- 
lessly gorge  itself  with  blood  and  then  drop 


ANNULATA,    SEGMENTED    WORMS  43 

off.  So  common  was  leeching  in  olden  times  that  doctors  were  often 
called  "leeches."  Although  not  so  commonly  used  in  medicine  at  the 
present  time  leeches  are  used  in  some  cases  to  remove  small  quantities 
of  blood  from  a  tender  or  sensitive  region.  It  is  also  said  that  leeches 
may  be  used  for  food,  but,  like  earthworms,  they  are  not  likely  to  be- 
come popular  articles  of  diet.  The  other  representatives  of  the  An- 
nulata,  though  of  great  scientific  interest  and  importance,  have  prac- 
tically no  economic  importance  except  as  scientific  specimens. 


CHAPTER  VIII 
MOLLUSCA 

The  mollusca  are  soft  bodied  (mollis,  soft)  animals,  usually  with 
an  external  shell  or  an  internal  "pen"  or  bone,  found  both  on  land  and 
in  fresh  and  salt  water.  They  are  primitively  bilaterally  symmetrical, 
but  this  symmetry  is  often  obscured  in  the  adults.  They  are  unseg- 
mented.  Although  the  various  classes  seem  at  first  glance,  very 
dissimilar,  yet  they  have  certain  structures  in  common  and  they  have 
a  similar  mode  of  development.  Two  characteristic  organs  of  the 


PIG.  28. — Fresh-water  mussel,  Anodon.  XM-  /»  foot,  protruded;  g,  line 
of  growth,  only  a  few  of  which  have  been  drawn;  ds,  dorsal  siphon;  Ig,  hinge  liga- 
ment; u,  umbo. 

phylum  are  the  foot,  variously  modified  for  different  uses,  and  the 
mantle,  inclosing  between  it  and  the  main  body  the  mantle  cavity 
into  which  the  digestive  and  urogenital  organs  open.  The  characters, 
mainly  of  the  foot,  mantle,  shell,  gills  and  nervous  system,  determine 
the  classification  of  the  phylum,  which  is  one  of  great  economic 
importance. 

Five  classes  are  usually  described. 

i.  Lamellibranchiata  or  Pelecypoda,  Fig.  28.  The  bivalves, 
such  as  oysters,  clams,  mussels,  etc.  Usually  bilaterally  symmetrical. 

44 


MOLLUSCA  45 

the  shell  consisting  of  two  more  or  less  similar  valves  and  the  mantle 
of  symmetrical  lobes. 

2.  Gastropoda,  Fig.  43. — These  molluscs  have  usually  a  single, 
spirally  coiled  shell,  and  are  not  bilaterally  symmetrical.     They  are 
the  snails,  slugs,  etc. 

3.  Cephalopoda,  Figs.  46  and  460.     Bilaterally  symmetrical  animals 
with  the  foot  divided  into  arms  which  are  provided  with  sucking  disks. 
Well-developed  nervous  system  concentrated  in'  the  head.     Usually 
with  a  spiral  external  shell  or  with  an  elongated  internal  bone  or  pen. 
Ink  sac  usually  present.     The  squids,  cuttlefishes,  octopi,  and  nautili. 

4.  Amphineura,  Fig.  47.     Bilaterally  symmetrical  forms  often  cov- 
ered with  eight  transverse  calcareous  plates.     Typically  represented 
by  the  chitons. 

5.  Scaphopoda,   Fig.  48.     A  small  group  of  small  marine  forms 
whose  tubular  mantle  secretes  a  slightly  curved,  conical  shell  open  at 
both  ends.     From  the  shape  of  the  white  shell  they  are  called  the 
elephants'  tusk  shells  or  tooth  shells. 

Shell-fish  have  been  used  as  food  by  man  from  prehistoric  times. 
At  various  places  along  the  sea-coast  huge  shell  mounds  or  "  kitchen  - 
middens"  are  found  as  relics  of  the  shell-fish  devoured  by  past  genera- 
tions, the  antiquity  of  which  is  indicated  by  the  primitive  implements 
sometimes  found  in  these  mounds. 

The  Oyster. — Of  all  molluscs,  certainly  of  those  found  in  America, 
the  oyster,  Ostrea  mrginiana  (virginica),  is  the  most  important  eco- 
nomically. A  generation  or  more  ago  there  were  dredged  in  Chesapeake 
Bay,  one  of  the  most  famous  regions  for  the  production  of  this  bivalve, 
each  year,  about  17,000,000  bushels  of  oysters.  These  oysters,  which 
were  the  "wild  crop"  obtained  without  cultivation,  were  shipped  alive 
and  in  cans  all  over  the  country.  The  supply  was  considered  to  be 
"inexhaustible."  Other  extensive  beds  are  found  in  Long  Island 
Sound,  in  Louisiana,  at  other  places  on  both  coasts,  in  Japan,  and  in 
various  European  countries. 

After  this  maximum  dredging  of  the  wild  crop  had  continued  for 
some  years  it  began  to  be  noticed  that  the  supposedly  inexhaustible 
supply  was  failing  and,  in  1882,  Dr.  W.  K.  Brooks,  of  Johns  Hopkins 
University,  was  appointed  by  the  Governor  of  Maryland,  a  commis- 
sioner to  investigate  the  oyster  business  and  to  make  recommendations 
for  its  improvement.  The  results  of  these  and  his  previous  investiga- 


46 


ECONOMIC   ZOOLOGY 


h 


PIG.  29. — An  oyster  in  the  right  valve  of  the  shell,  dissected  so  as  to  show  the 
internal  organs.  The  anterior  end  of  the  body  is  at  the  top  of  the  figure,  and  the 
dorsal  surface  on  the  right  hand.  Xi.  b,  the  mantle;  c,  the  muscle;  d,  the  heart; 
g,  the  gill;  h,  the  lips;  *',  the  intestine;  j,  the  liver;  m,  the  mouth;  s,  the  stomach. 
(From  Brooks,  The  Oyster.) 


MOLLUSCA  47 

tions  were  published  by  Brooks  in  his  book,  "The  Oyster,"  in  which 
he  described  in  a  popular  yet  scientific  way,  the  natural  history  of  the 
American  oyster,  and  showed  the  necessity  of  conserving  the  supply  by 
proper  cultivation  just  as  is  done  with  most  other  natural  food  prod- 
ucts. The  food  of  the  oyster  consists  of  microscopic  organisms  living 
in  the  salt  or  brackish  water  in  which  the  oyster  thrives  best.  They 
are  carried  into  the  mantle  chamber,  Fig.  29,  by  the  cilia  cover- 
ing the  organs  of  that  region  and  enter  the  mouth  of  the  animal. 
Among  these  organisms,  of  course,  may  be  disease  germs,  if  the  water 
be  polluted  with  sewage,  as  will  be  noted  below.  It  requires  three  or 
four  years,  depending  on  the  food  supply,  etc.,  for  the  oyster  to  reach 
maturity. 

In  the  European  oyster  the  eggs  are  fertilized  and  begin  their  de- 
velopment in  the  gill  tubes  of  the  female,  while  in  the  American  form  it 
was  found  by  Brooks  that  the  eggs  are  fertilized  outside  of  the  female, 
in  the  surrounding  water.  Since  an  average  Maryland  oyster  will 
lay  the  incredible  number  of  16,000,000  eggs  per  year,  it  is  evident  that 
the  struggle  for  existence  must  be  terrific  or  the  sea  would  soon  be  filled 
with  oysters.  If  the  egg  should  happen  to  be  fertilized,  it  segments 
and  develops  into  a  tiny  ciliated  larva  which  swims  to  the  surface,  where 
it  may  be  killed  by  a  heavy  rain.  After  living  for  a  time  at  the  surface, 
if  it  escape  its  many  perils,  it  sinks  to  the  botUta,  loses  its  cilia,  devel- 
ops a  tiny  shell,  and  attaches  itself  to  some  solid  object,  if  such  be 
found,  and  is  known  as  a  "spat; "  if  no  solid  object  be  present  the  young 
oyster  will  perish,  but  if  it  succeed  in  becoming  "set"  it  will  proceed  to 
develop  into  the  mature  oyster. 

Oyster  Culture. — Brooks  found  that  by  mixing  eggs  and  sperm  from 
"ripe"  oysters  in  salt  water  the  eggs  could  be  easily  fertilized  in  un- 
limited numbers;  but,  for  some  reason,  these  artificially  fertilized 
eggs  when  they  develop  to  the  spat  stage  will  not  set,  so  that  this  stage 
of  oyster  culture  is  not  practicable.  What  may  be  done  is  to  allow  the 
spat  to  form  in  the  natural  way  and  then  collect  it  by  placing  various 
kinds  of  hard  objects  in  the  water  at  the  breeding  season;  if  placed 
in  the  water  too  long  before  the  spat  are  ready  to  set  these  solid  objects, 
known  collectively  as  "cultch,"  may  become  covered  with  mud  or 
other  sediment  and  thus  prevent  the  spat  from  setting.  Various  sub- 
stances are  used  as  cultch:  tiles;  a  bunch  of  twigs  (bamboo  in  Japan) 
tied  together  and  sunk  to  the  bottom  with  a  stone;  crushed  rock;  scrap 


48 


ECONOMIC   ZOOLOGY 


tin  from  can  factories;  scallop  shells;  and  especially  oyster  shells.  New 
beds  may  be  started  by  spreading  the  cultch  over  the  bottom  at  the 
breeding  season  and  then  distributing  "wild"  oysters,  that  are  about  to 
spawn,  over  the  cultch.  After  the  spat  has  "set"  over  the  cultch  and 
has  grown  into  "seed"  oysters  of  an  average  size  of  half  a  dollar,  the 
cultch  may  be  collected,  broken  up  and  spread  over  the  bottom  again 
to  prevent  the  growing  oysters  from  crowding  each  other,  Figs.  29 


PIG.  30. — A  bed    of    well-shaped,   ^marketable     oysters. 
Grave,  from  Brooks,  The  Oyster.) 


X  Ko-     (Photograph   by 


and  30.  This  is  the  general  method  of  oyster  culture  as  carried  on  in 
many  places.  Of  course,  it  necessitates  a  survey  of  all  the  oyster 
grounds,  just  as  farms  are  laid  out,  in  order  that  dishonest  dredgers, 
of  which  there  are  many,  may  not  reap  where  others  have  sown.  It  is 
also  obviously  more  troublesome  than  harvesting  the  "wild"  crop, 
but  unless  some  sort  of  culture  be  adopted  the  wild  crop  will  inevitably 
become  exhausted.  The  most  serious  difficulty  in  such  cases  always 


MOLLUSCA 


49 


PIG.  31. — Upper  figure,  an  oyster  shell  to  which  about  150  young  oysters  have 
attached  themselves.  Lower  figure,  a  pipe  from  Chesapeake  Bay  upon  which 
six  oysters  have  grown.  (From  Brooks,  The  Oyster.') 


ECONOMIC  ZOOLOGY 


is  to  get  the  proper  legislation  enacted     by  ignorant  or  dishonest 
legislatures. 

There  are  various  difficulties  with  which  the  oyster  farmer  has  to 
contend.  If  the  water  be  too  cold  the  oysters  may  grow  but  not  repro- 
duce; if  it  be  too  shallow  it  may  freeze  in  exceptionally  cold  weather; 
the  salinity  of  the  water  may  not  be  right. 

Although  there  are  no  known  epidemic  diseases  of  oysters,  there  are 
several  enemies  that  cause  trouble;  the  worst  of  these  is  the  starfish, 

as  has  been  noted  in  connection 
with  the  Echinodermata;  while 
not  found  in  the  southern  beds  it 
is  so  numerous  and  destructive 
farther  north  as  to  make  oyster 
culture  impossible  without  active 
warfare  against  this  enemy.  They 
multiply  very  rapidly,  where  con- 
ditions are  favorable.  The  best 
means  of  destroying  them  is  to 
catch  them  on  a  "  tangle,"  Fig. 
32,  of  frayed  rope  and  then  kill 
them  by  plunging  them  into  a 
tank  of  hot  water.  If  cut  to  pieces 
and  thrown  back  into  the  water 
the  menace  is  increased,  as  many 
of  the  pieces  will  grow  into  com- 
plete starfish  and  thereby  increase 
the  total  number  of  the  pests. 

There  are  several  snails,  known 
as  "drills"  that  are  often  quite 
destructive  by  boring  through  the 

shells,  especially  of  young  oysters.  There  are  several  fish  such  as  the 
drum,  sheepshead,  skate,  etc.,  that  are  injurious;  and  the  oysters  are 
sometimes  smothered  by  mussels,  sponges,  sea-weeds  and  drifting  sands. 
Oysters  are  collected  with  tongs  or  by  dredging.  The  former, 
Fig.  33,  might  be  compared  to  a  pair  of  heavy  iron  rakes  with  very 
long  handles  that  are  joined,  scissors- wise,  near  the  rakes.  The  tonger 
may  stand  in  the  stern  of  a  row-boat  or  at  the  side  of  a  larger  boat 
and  by  a  scissors  motion  scrape  off  the  oysters  from  the  bottom  until 


PIG.  32. — A  "tangle"  of  frayed  rope 
or  cotton  waste  used  to  collect  starfish 
from  oyster  beds.  (After  J.  L.  Kellogg, 
Shellfish  Industries,  from  U.  S.  Fish 
Commission.) 


MOLLUSCA  51 

his  tongs  are  full  and  then  lift  them  up  and  empty  them  in  the  boat. 
The  size  of  the  tongs  varies,  the  shortest  handles  being  about  12  feet. 
They  are  used  by  the  poorer  oyster  men,  often  in  water  too  shallow 
for  larger  dredging  boats.  While  10  to  15  feet  is  the  usual  depth,  they 
may  be  used  in  water  as  much  as  30  feet  deep.  Needless  to  say  tonging 
is  very  hard  and,  in  cold  weather,  very  exposing  work. 

The  more  modern  and  much  more  rapid  method  of  collecting  oysters 
is  by  means  of  the  dredge,  an  iron  frame  with  a  heavy  net  behind  to 
hold  the  oysters  that  the  frame  detaches  from  the  bottom.  The  dredge 


FIG.  33. — Oyster  tongs.     Laboratory   employees  tonging  and   culling   oysters  in 
Louisiana.     (After  J .  L.  Kellogg,  Shellfish  Industries.) 

is  used  on  larger  sailing  or  steam  vessels  and  may  be  hauled,  by  steam 
power,  Fig.  34,  from  any  depth  at  which  the  oysters  are  found.  "Oys- 
ters that  grow  on  trees"  are  a  curiosity  of  the  tropics,  they  are  simply 
oysters  that  become  attached  to  the  submerged  roots  of  aquatic  trees 
(i.e.,  mangrove).  The  small  mangrove  oysters  of  the  West  Indies  are 
collected  and  sold  in  considerable  numbers. 

As  noted  above  the  oyster  in  feeding  will  take  into  itself  any  disease 
germs  that  may  be  in  the  surrounding  water.  The  germs  that  enter 
the  digestive  tract  are  doubtless  soon  destroyed,  but  where  present  in 


52  ECONOMIC   ZOOLOGY 

the  water  they  will  adhere  to  the  gills  and  other  organs  of  the  oyster 
and  may,  if  the  oyster  be  eaten  raw,  thus  enter  the  human  system. 

Although  denied  by  some,  there  have  been  numerous  cases  of 
typhoid  fever  and  other  diseases  that  have  been  traced  to  contaminated 
oysters.  It  is  claimed  by  some  oystermen  that  during  the  cold  weather, 
when  oysters  are  most  in  demand,  they  are,  in  a  sense,  hibernating  and 
take  no  food  so  that  they  cannot  be  seriously  contaminated  with  disease 
germs.  Whether  or  not,  this  be  true  it  is  obviously  important  to  see  that 
no  oysters  be  sold  that  are  taken  from  beds  that  are  contaminated  by 


FIG.  34. — A  steam  power  oyster  dredge.      (After  J.  L.  Kellogg,  Shellfish  Industries, 
from  a  Report  of  the  N.  Y.  Forest,  Fish  and  Game  Commission.') 

sewage;  most,  if  not  all,  of  the  States  possessing  oyster  grounds  now  have 
laws  that  are  supposed  to  prevent  this  danger.  In  some  cases  oysters 
from  contaminated  beds  may  be  made  safe  by  transplanting  them  for  a 
certain  length  of  time  to  pure  water,  until  they  are  free  from  pathogenic 
organisms. 

There  are  federal  laws  that  regulate  the  interstate  shipment  of 
oysters  except  in  sanitary  ways,  either  in  the  shell  or  in  sealed  tin 
or  glass  vessels,  surrounded  by  ice.  A  bivalve  that  has  opened  its 


MOLLUSCA 


53 


shell  is  not  fit  for  food  but  it  cannot  contaminate  those  that  are  still 
closed. 

The  custom  of  "  floating"  oysters  has  been  considerably  discussed. 
By  a  "floated"  oyster  is  meant  one  that  has  been  brought  into  water 
of  less  salinity  than  that  in  which  it  grew,  until  it  has  absorbed  this 
fresh  water  and  thereby  become  swollen  or  bloated.  This  custom,  when 
the  fresh  water  is  contaminated  by  sewage,  as  it  often  is  near  cities, 


FIG.  35. — Long-neck  clam,  My  a,  with  byssus,  b,  attached  to  sand  grains,  sg. 
J.  L.  Kellogg,  Shellfish  Industries.) 


(After 


was  a  serious  source  of  contamination  and  was  justly  condemned;  but  if 
the  water  be  pure  the  floating  merely  makes  the  oysters  bulkier  (by  as 
much  as  20  per  cent.,  at  times),  and  thereby  diminishes  their  food  value, 
when  bought  by  the  quart  or  gallon.  For  this  reason  the  pure  food 
laws  require  "floated"  oysters  to  be  so  labeled.  The  floating  also 
diminishes  the  salty  taste  of  the  oysters,  which  makes  them  more  agree- 
able to  some  palates. 

Soft  or  long  neck  dam,  Mya  arenaria,  Fig.  35.     This  is  the  clam 
of  New  England,  famous  in  clam  chowders  and  clam  bakes.     It  is 


54  ECONOMIC   ZOOLOGY 

essentially  a  northern  form  where  it  was  formerly  found  in  enormous 
numbers.  It  spends  most  of  its  time  buried  in  the  sand  or  mud,  some- 
times to  a  depth  of  a  foot.  Its  long  siphons  (neck)  reach  to  the  surface 
of  the  sand  and  are  withdrawn  when  the  sand  is  left  bare  by  the  re- 
treating tide,  leaving  the  characteristic  hole  that  reveals  the  presence 
of  the  hidden  clam,  Fig.  36.  The  clams  are  obtained  by  digging  them 
a  low  tide  with  a  sort  of  short-handled,  long-tined  rake,  shown  in 
Fig.  36.  The  number  of  clams  obtained  under  favorable  conditions 
from  a  given  area  is  sometimes  astonishing,  Fig.  37.  The  shells  being 
thin  (soft),  they  are  often  broken  in  digging  them  out  of  the  sand. 


FIG.  36. — Beach  showing  very  numerous  holes  of  long-neck  clams.  Clam 
rake  in  foreground.  {After  J.  L.  Kellogg,  Shellfish  Industries,  from  Report  of  Mass. 
Fish  and  Game  Commission  by  Belding.) 

Clam  Culture. — Although  the  conditions  suitable  for  the  culture  of 
soft  clams  are  quite  different  from  those  noted  above  for  oysters,  they 
are  not  unusual  and  are  fairly  well  understood;  it  is  estimated  that 
400  bushels  per  acre,  at  a  profit  of  75  cents  per  bushel,  could  be 
raised.  The  chief  difficulty  in  the  way  of  successful  clam  culture  is 
that  the  laws  of  some  States  make  the  clam  bottoms  public  lands,  so 
that  the  man  who  cultivates  clams  has  no  legal  right  to  protect  his 
plantings  against  trespass  and  theft.  This  clam  has  been  transplanted 
to  the  Pacific  coast  where  it  apparently  thrives  and  may  become  an 
important  source  of  food  for  that  region. 

Hard  or  little  neck  clam,  quahog,  Venus  mercenaria,  Fig.  38.  This 
clam  is  common  along  the  entire  Atlantic  coast,  but  for  some'rea- 


MOLLUSCA 


55 


son  is  seldom  eaten  in  the  south  where  it  is  most  abundant.  The 
massiveness  of  its  valves  has  given  the  name  "hard,"  the  shortness  of 
its  siphons  the  name  " little  neck,"  and  the  name  "quahog"  or 
"quahang,"  is  said  to  be  derived  from  an  Indian  name  meaning 
"tightly  closed."  The  smaller  specimens,  which  may  bring  $4  a 
bushel,  are  served  in  restaurants  as  "little  necks,"  to  be  eaten  raw 
from  the  half  shell.  Though  sometimes  found  between  tides,  the 


FIG.  37. — Long-neck  clams  dug  from  beneath  one  square  foot  of  a  flat.  Such 
a  yield  is  unusual.  The  ruler  is  six  inches  long.  (After  J.  L.  Kellogg,  Shellfish 
Industries,  from  Report  of  Mass.  Game  and  Fish  Commission  by  J.  R.  Stevenson.) 


quahog  usually  occurs  in  greater  numbers  in  deeper  water  and  is 
collected  from  such  beds  with  a  large  rake  with  long,  steel  teeth  and 
a  han  lie  as  much  as  60  feet  long,  so  that  their  collection  is  very  laborious. 
The  clam  has  few  enemies  in  its  natural  habitat  and  is  so  very  hardy 
that  it  may  be  transported  almost  any  distance,  even  in  warm  weather. 
Like  the  oyster,  many  of  the  northern  quahog  beds  were  dredged 


50  ECONOMIC   ZOOLOGY 

till  depleted,  so  that  the  canneries  were  compelled  to  move  south  to 
new  beds. 

The  only  effort,  apparently,  to  conserve  the  supply  that  has  been 
made  has  been  to  declare  an  occasional  closed  season.  Enough  experi- 
mental work  has  been  done  to  indicate  that  culture  of  this  clam  might 
be  carried  on  at  a  good  profit. 

Scallop,  Pecten  irradians  and  P.  tenuico  status,  Fig.  39.  These  two 
species  are  found  along  the  Atlantic  coast,  the  former  in  more  shallow 
waters,  from  Cape  Cod  to  Texas,  the  latter  in  deeper  waters,  north  of 
Cape  Cod.  The  southern  form  seldom  exceeds  3  inches  in  diameter 
and  is  the  more  common  of  the  two,  the.  northern  species  may  reach 
a  diameter  of  7  inches. 


PIG.  38. — Hard-shell  clam  or  quahog, 
Venus  mercenaria.      X/^. 


PIG.  39. — Scallop  shell,  Pecten 
irradians.      X- 


The  only  part  that  is  usually  eaten  is  the  small,  cylindrical  adductor 
muscle,  though  the  rest  is  perfectly  good  food.  These  meats  are 
freshened  by  soaking  them  in  fresh  water;  this  process  swells  them 
greatly  and  of  course  increases  the  value  of  animals  sold  by  bulk, 
though  it  makes  them  spoil  much  more  quickly. 

Pecten  does  not  lie  buried  as  do  the  preceding  two  forms,  but  moves 
about  more  or  less  actively  by  opening  and  shutting  its  shell,  so  that  it 
is  dredged  by  means  of  a  "pusher,"  a  rectangular  iron  frame  with  a  bag 
at  the  back. 

Owing  to  their  perishability  and  the  limited  supply  scallops  are 
not  used  to  any  great  extent  at  a  distance  from  the  coast.  As  the  price 
is  sometimes  as  high  as  $5  a  gallon,  wholesale,  they  may  be  consid- 


MOLLUSCA 


57 


ered   a  luxury.     What   might  be  expected  from  scallop  culture  it  is 
difficult  to  say. 

Sea  mussel,  salt  water  mussel,  Mytilus  edulis,  Fig.  40.  The  sea 
mussels  have  for  ages  been  an  important  article  of  diet  in  Europe,  but, 
for  some  reason,  they  have  never  become  popular  in  America,  though 
the  natural  beds  would  supply  large  quantities  at  a  low  cost,  and  by 
proper  cultivation  they  might  rival  the  oyster  in  importance ;  Field  (82) 
summarizes  his  investigations  upon  the  sea  mussels  as  follows: 

"i.  The  sea  mussel,  Mytilus  edulis  Linnaeus,  is  not  utilized  as  a  food 
to  any  extent  in  the  United  States  outside  of  the  vicinity  of  New  York  City. 

"2.  As  a  food  material  it  is  superior  to  many  articles  which  are  com- 
monly eaten.  Scores  of  persons  have  pronounced  it  to  be  equal  in  flavor, 


PIG.  40. — Edible  salt  water  mussel,  Mytilus  edulis.      X%. 

or  even  superior,  to  the  oyster;  it  is  easily  digested,  has  a  high  nutritive  value, 
and  is  exceedingly  abundant  and  general  in  its  range. 

"3.  Along  most  of  our  eastern  coast  the  mussel  is  in  season  for  food  when 
the  oyster  is  out  of  season. 

"4.  The  mussel  is  well  adapted  to  preservation.  When  canned  or  pickled 
it  will  retain  its  natural  flavor  for  months. 

"5.  The  mussel  breeds  at  a  prolific  rate,  it  develops  rapidly,  requires 
less  special  conditions  for  growth  than  the  oyster,  and  may  therefore  be 
easily  cultivated. 

''6.  The  only  difficulty  in  the  marketing  of  mussels  for  food  purposes  is 
that  they  spoil  quickly  after  being  removed  from  the  water.  It  is  necessary 
to  use  them  within  24  hours  after  they  are  collected  or  ptomaine 
poisoning  may  result.  To  insure  one's  self  against  illness  from  eating  them, 
the  mussels  must  be  taken  from  water  that  is  pure  and  subject  to  the  constant 
circulation  of  tidal  currents. 


58  ECONOMIC   ZOOLOGY 

"7.  Other  important  ways  for  utilizing  mussels  are  as  bait  for  the  fisheries 
and  as  fertilizer  for  the  soil  on  which  onions  and  carrots  are  to  be  raised  ..." 

Edible  Snails. — There  are  various  species  of  snails  that  are  used 
for  food,  most  of  them  belonging  to  the  common  genus  Helix;  they  are, 
of  course,  Gastropods.  The  eating  of  snails  was  known  in  Italy  before 
the  Christian  era;  the  custom  was  introduced  into  France  in  the  latter 
part  of  the  eighteenth  century  which  country  is  now  the  chief  consumer 
of  this  mollusc.  It  is  estimated  that  in  Paris  alone  200,000,000  snails 
are  consumed  in  a  season,  September  to  April — the  price  varying 
from  50  cents  to  $2  depending  on  the  species,  quality,  etc.  They  are 
a  delicacy,  not  a  staple  article  of  food,  like  beef. 

Snail  farms  or  "snaileries"  are  common  in  southern  France,  in  Italy, 
and  in  Spain,  though  the  business  is  not  so  profitable  as  formerly.  The 


FIG.  41. — Shell  of  Abalone,  Haliotissp. 

snails  are  collected  in  the  woods  by  peasants;  they  are  put  in  "pens" 
or  "gardens"  surrounded  by  a  low  fence  of  wire  netting,  about  10,000 
snails  in  a  pen  25-30  feet  square.  They  are  fed  on  all  kinds  of  vege- 
tables or  on  bran-mash.  Each  snail  lays  about  50  to  60  eggs  in 
the  summer,  which  hatch  and  become  sexually  mature  the  next  summer, 
but  do  not  reach  their  full  size  until  the  second  summer. 

They  are  cooked  in  various  ways:  i.e.,  they  may  be  boiled,  picked 
out  of  the  shells,  minced,  flavored  and  then  stuffed  into  the  shells  again. 
They  could  probably  be  easily  raised  in  the  United  States  in  places 
that  are  useless  for  other  purposes,  but  a  popular  taste  would  have 
to  be  created  or  they  would  have  no  market. 

Abalone,  genus  Haliotis,  Fig.  41.  This  familiar  gastropod  of  the 
western  coast  is  useful  both  for  food  and  in  the  manufacture  of  orna- 


MOLLUSCA  59 

merits  from  its  shell.     In  some  species  the  shell  when  polished   is 
wonderfully  fine  mother-of-pearl,  with  all  sorts  of  brilliant  colors. 

Window-glass  shell,  Placuna  placenta,  Fig.  42.  This  curious  bivalve 
has  shells  so  thin  and  flat  that  they  may  be  cut  into  squares  of  3  or 
4  inches  and  set  in  window  sash  for  lighting  houses.  Their  pearly 
translucency  is  very  pleasing,  and  they  are  very  widely  used  in  some 
parts  of  the  tropics,  for  residences,  churches  and  other  buildings. 

"The  demand  for  window  shell  in  other  countries  for  the  manufacture 
of  lantern  shades,  screens,  etc.,  in  addition  to  the  local  use  for  windows, 
has  so  increased  that  there  is  danger  of  exceeding  the  supply.  In  the 
early  part  of  the  year  the  Bureau  of  Science  undertook  the  planting  of  a 
new  bed  of  these  shells.  Five  thousand  live  shells  were  taken  in  Kawit 


PIG.  42. — Window  shell,  Placuna  sp.,  and  square  cut  from  a  shell.      xM- 

and  planted  on  the  mud  bottom  of  the  esteros  and  oyster  beds  at  Malabon. 
I  believe  these  will  thrive,  if  they  are  not  removed  by  the  local  fishermen." 
From  repprt  of  Director  Alvin  Cox,  Phila.  Bu.  Sc. 

Camto  or  helmet  shells,  genus  Cassis.  These  Gastropod  shells  owe 
their  value  to  the  fact  that  they  are  composed  of  different  colored 
layers — white  and  black  for  example — so  that  a  figure  may  be  carved 
out  of  one  color  with  the  other  color  as  a  background.  The  carving  of 
cameos,  so  important  in  Italy,  has,  it  is  said,  degenerated  from  an  art 
to  a  trade,  so  that  the  fashion  has  greatly  declined. 

Giant  clams,  genus  Tridacna.  These  are  the  largest  of  the  lamelli- 
branchs  and  may  reach  a  weight  of  500  pounds.  They  are  found  in 
the  oriental  tropics  and  are  said  to  sometimes  drown  pearl  divers  who 
happen  to  be  caught  between  their  mammoth  valves.  The  valves 


6o 


ECONOMIC   ZOOLOGY 


which  may  be  a  beautiful  pure  white  color  within  are  often  used  as 
fonts  for  holding  holy-water  in  churches. 

In  parts  of  Africa  and  India  cowries  or  porcelain  shells  are  used 
as  money  and  the  well-known  wampum  of  the  American  Indians  was 
made  from  the  shells  of  the  quahog,  especially  those  that  were  lined 
with  blue,  and  from  the  colored  adductor  muscle  scars  of  other  lamel- 
libranchs. 


FIG.  43 — A  gastropod  shell,  Murex  sp.      xM- 

Pearls  and  Mother-of-pearl. — The  shells  of  lamellibranchs  are  se- 
creted by  the  mantle.  In  most  species  this  secretion  is  mainly  a  dull 
white  calcium  carbonate,  but  in  some  species  it  is  laid  down  in  glossy 
iridescent  layers  and  is  known  as  mother-of-pearl.  If  of  a  fine  qual- 
ity, it  may  be  used  for  various  ornamental  purposes;  if  of  a  less  fine 
grade  it  may  still  be  used  in  the  manufacture  of  pearl  buttons.  The 
pearls,  which  may  be  attached  to  the  inside  of  the  shell  or  may  be  free 
between  the  shell  and  the  mantle,  are  formed  by  the  same  glands  of  the 


MOLLUSCA  6 1 

mantle  around  some  small  foreign  body  as  a  nucleus.  This  foreign 
body  may  be  a  grain  of  sand,  a  dead  egg,  a  dead  parasite,  or  a  small 
shot  or  other  object  introduced  by  man  between  the  shell  and  the 
mantle.  The  irritation  of  this  foreign  body  probably  causes  an  active 
secretion  by  the  mantle  glands  of  the  nacreous  material  in  concentric 
layers  over  the  offending  object,  the  result  being  a  pearl,  whose  value 
depends  upon  its  size,  shape,  color,  etc.  If  the  pearl  be  attached  to  the 
shell  it  will,  of  course,  have  to  be  cut  free,  which  will  leave  a  scar  on  one 
side  and  render  it  fit  only  for  a  setting  where  this  side  will  be  hidden. 
In  some  places,  it  is  said,  fine  shot  are  introduced  between  the  mantle 
and  shell  to  act  as  nuclei  for  pearls;  the  oyster  is  then  replaced  in  the 
water  to  be  examined  for  pearls  at  a  later  date. 

This  characteristic  of  the  mantle  has  been  made  use  of  in  producing 
the  sacred  clam  shells  that  the  Chinese  Buddhists  believe  to  have  a  mi- 
raculous origin,  and  that  are  sometimes  seen  in  collections.  Brooks 
(79)  says: 

"The  inside  of  the  shell  has  a  beautiful  pearl  lustre,  and  along  it  is  a  row 
of  little  fat  images  of  Buddha,  squatting  with  his. legs  crossed  under  him, 
and  his  elbows  on  his  knees.  They  are  formed  of  pearl  precisely  like  that 
which  lines  the  rest  of  the  shell,  a  little  raised  above  its  surface  and  outlined 
in  faint  relief,  but  they  are  a  part  of  the  shell,  with  no  break  or  joint.  In 
the  process  of  manufacturing  them,  the  shell  of  the  living  animal  is  wedged 
open,  and  thin  images,  punched  out  of  a  sheet  of  bell-metal,  are  inserted. 
The  animal  is  then  returned  to  the  water,  and  is  left  there  until  enough  new 
shell  has  been  formed  to  cover  them  with  a  varnish  of  pearl  thick  enough  to 
fasten  them,  and  to  hide  the  metal,  while  permitting  the  raised  outline  to  be 
seen." 

Although  pearls  of  considerable  size  are  often  found  in  the  edible 
oysters  and  other  bivalves  they  have  little  value,  as  the  glands  of 
the  mantle  do  not  secrete  the  proper  nacreous  material. 

The  precious  pearls  are  found  chiefly  in  the  pearl  oysters  of  the 
family  Amculidce  and  in  the  pearl-bearing  mussels  of  the  family  Union- 
ida.  The  true  pearl  oysters  are  found  in  the  Indian  Ocean,  Red  Sea, 
Gulf  of  California  and  elsewhere,  though  the  value  of  the  pearls  and 
mother-of-pearl  varies  greatly  in  different  localities.  In  some  places 
the*shells  are  heavy  and  of  fine  quality  and  may  be  worth  50  cents 
each;  in  other  places  they  are  thrown  away  and  only  the  pearls  are 
sought. 


62  ECONOMIC   ZOOLOGY 

The  oldest  pearl  fisheries  are  on  the  north  coast  of  the  island  of 
Ceylon,  where  pearls  have  been  collected  since  the  beginning  of  the 
Christian  era. 

Since  the  British  occupation  the  fisheries  have  been  under  govern 
ment  control  and  have  been  a  great  source  of  revenue. 

At  certain  intervals  the  government  will  advertise  an  open  season 
for  pearl  diving  and  the  natives  flock  to  the  fishing  grounds  by  the 
thousands.  At  a  given  signal,  each  day  the  boats  set  out,  and  at  the 
end  of  the  day  a  second  signal  recalls  them  to  shore.  Small  boats  are 
used,  each  with  10  divers,  in  two  gangs,  an  equal  number  of  helpers, 
and  two  or  three  sailors.  The  diver  descends  to  the  bottom,  30  to 
50  feet,  with  the  aid  of  a  heavy  stone,  works  for  30-90  seconds  and 
is  drawn  up  with  his  basket  of  oysters.  At  the  end  of  the  day  the  oys- 
ters are  taken  to  shore  and  placed  in  bins  to  decay.  When  thoroughly 
decayed  they  are  carefully  washed  and  examined  for  pearls;  the  stench 
may  be  imagined.  The  government  claims  a  certain  proportion  of  the 
shells  and  the  divers  take  the  rest.  It  makes  an  interesting  form  of 
gamble,  as  a  collection  of  shells  may  have  $10,000  worth  of  pearls  or 
it  may  contain  none.  For  miles  the  shore  is  covered  several  feet  deep 
with  shells. 

In  America  the  most  important  pearl  fisheries  are  in  the  Gulf  of 
California,  centering  about  La  Paz.  These  fisheries  were  operated  by 
Indians  in  the  time  of  Cortez  and  were  exploited  by  the  Spanish  govern- 
ment. The  season  here  is  from  June  to  December.  The  expert  Indian 
and  Mexican  divers,  who  were  said  to  work  on  an  empty  stomach  to 
increase  the  lung  capacity,  have  been  largely  replaced  by  the  present 
operators,  chiefly  San  Francisco  firms.  Each  boat  now  has  a  diving 
outfit,  with  one  diver  and  a  proper  number  of  pump  men  and  other 
helpers.  About  300  oysters  per  day  are  collected  by  such  a  boat. 

There  are  also  'fisheries  on  the  coasts  of  Panama,  Guatamala,  Red 
Sea,  South  Sea  Islands,  Australia,  the  Sulu  Islands,  and  elsewhere.  In 
the  latter  two  regions  the  shells  are  particularly  fine  and  are  collected 
for  mother-of-pearl.  At  the  town  of  Jolo,  capital  of  the  Sulu  group 
the  writer  was  asked  one  peso  (50  cents)  for  a  single  valve  of  a  large 
pearl  oyster. 

Some  of  the  fresh-water  mussels  (Unionidae),  Fig.  28,  of  Asia, 
Europe  and  America  are  valuable  both  for  pearls  and  for  use  in  making 
pearl  buttons.  On  account  of  their  unusual  color  the  pearls  are  often 


MOLLUSCA  63 

very  valuable,  but  in  America  they  have  never  been  very  systemati- 
cally sought,  being"mainly  collected  by  farmers  and  others  in  a  very 
wasteful  manner.  In  Europe  the  supply  has  been  conserved  by  care- 
fully opening  the  shells  with  specially  devised  tools  and  returning  the 
animals  to  the  water  after  examination. 

In  America  the  Unionidae  are  chiefly  used  for  buttons  and  along  the 
Ohio  and  Mississippi  Rivers  they  have  been  so  extensively  dredged  that 
they  are  threatened  with  extermination.  The  shells  are  drilled  with 
tube-shaped  drills  that  cut  out  disks  of  pearl  from  about  5  mm.  to  30 
mm.  or  more  in  diameter,  Fig.  44;  from  these  rough  disks  the  pearl  but- 


FIG.  44. — Ohio  River  pearl  mussel,  Unio  sp.,  from  which  15  button  discs  have  been 
cut.     Above  are  3  discs  of  different  sizes.      X/^. 

tons  are  made.  Several  dozen  disks  may  be  drilled  from  one  shell,  the 
number  varying,  of  course,  with  the  size  of  the  disks  and  the  size  of  the 
shell. 

In  both  the  pearl-bearing  oysters  and  pearl-bearing  mussels  pearls 
are  most  likely  to  be  found  in  distorted  and  abnormal  specimens. 

Ship-worms. — Of  the  few  molluscs  that  are  of  negative  economic 
importance  probably  the  most  injurious  are  the  ship-worms,  Teredo 
navalis  and  other  species.  In  the  days  when  all  vessels  were  made  of 
wood  and  were  unprotected  with  metal  sheathing  these  boring  bivalves 
must  have  been,  indeed,  the  ''terror  of  ships."  Though  they  belong 
to  the  class  of  Lamellibranchs  they  are  elongated,  worm-like  animals, 
and  hence  have  been  called  ship-worms.  They  may  reach  a  length  of 


64 


ECONOMIC   ZOOLOGY 


4  feet  and  a  diameter  of  i  inch,  Fig.  45.  Sigerfoos  (52)  estimates 
that  a  single  large  female  may  lay  100,000,000  eggs.  These  eggs 
rapidly  develop  into  free-swimming  larvae,  typical  of  the  lamelli- 
branchs.  After  further  development  these  larvae  attach  themselves 


FIG.  45. — A  ship-worm,  Teredo  navalis,  in  a  piece  of  timber.  Xi.  p,  pallets; 
55,  siphons;  T,  tube;  V,  valves  of  shell.  (From  Hegner,  College  Zoology,  after 
Cambridge  Natural  History  from  Mobius.) 

to  some  submerged  piece  of  wood  and  begin  to  burrow  into  it,  gradually 
changing  to  the  worm-like  form  as  they  clo  so.  The  newly  attached 
larvae  are  tiny  animals,  abotft  0.2.$  mm.,  long;  on  entering  the  wood 
they  grow  rapidly  so  that  in  about  five  weeks,  in  some  species,  they 


FIG.  46. — Devil-fish,  Octopus  sp. 


may  be  100  mm.  long.  Sigerfoos  estimated  that  a  four-foot  specimen 
was  only  about  a  year  old.  The  rate  of  growth  seems  to  be  independent 
of  the  kind  of  wood,  whether  it  be  soft  white  pine  or  hard  oak;  probably 
the  food  supply  is  the  determining  factor.  In  a  four-foot  worm  the 


MOLLUSCA  65 

valves  are  an  inch  or  less  in  length  and  are  the  means  by  which  the 
worm  bores  its  way  into  the  wood.  The  rest  of  the  soft  body  is  uncov- 
ered so  that  the  animal  secretes  a  thin,  smooth  calcareous  lining  to  its 


FIG.  460. — Squid,  Loligo  pealii. 


burrow  to  protect  itself  from  the  rough  edges  of  the  wood.  If  the  larvae 
settle  at  the  end  of  a  log  they  burrow  straight  ahead  in  the  direction 
of  the  grain  of  the  wood,  but  if  they  settle  on  the  side  of  the  log,  they 
bore  across  the  grain  for  a  short  distance,  usually  within  2  inches, 


66  ECONOMIC  ZOOLOGY 

then  turn  the  direction  of  their  operations  so  as  to  work  with  the  grain, 
Fig.  45.  As  the  worm  increases  in  size  it,  of  course,  enlarges  the  di- 
ameter of  its  hole  which  thereby  becomes  conical  in  shape,  as  shown  in 
Fig.  45.  The  much  elongated  body  and  siphons,  Fig.  45,  ss,  extend 
posteriorly  to  the  opening  of  the  tube  and  the  latter  serve  to  conduct  a 


FIG.  47. — A  chiton.      Xi. 

stream  of  water  to  the  animal  (just  as  in  ordinary  Lamellibranchs) 
from  which  food  is  extracted  in  the  form  of  microscopic  organisms.  At 
the  base  of  the  siphons  are  two  small  calcareous  bodies  known  as 
pallets,  Fig.  45,  p,  which  serve  to  close  the  opening  of  the  burrow  against 
an  enemy  or  to  retain  the  water  should  the  low  tide  leave  the  wood 
exposed.  The  method  of  boring  of  ship-worms  has  been 
a  much  debated  question;  it  is  apparently  accomplished 
by  the  rasping  action  of  the  posterior  edges  of  the  valves 
as  they  are  rocked  back  and  forth  by  the  alternate 
action  of  the  anterior  and  posterior  adductor  muscles, 
the  shell  being  pressed  against  the  end  of  the  burrow 
FIG.  48.—  by  the  cupping  action  of  the  foot.  The  particles  of 
wood  that  are  rasped  away  are  ingested  and  thus 
Dentaiium.  passed  out  of  the  burrow,  but  whether  the  animal  de- 
rives any  nourishment  from  them  is  a  debated  question. 
While  the  introduction  of  steel  ships  and  the  sheathing  of  wooden 
ones  with  metal  have  largely  diminished  the  havoc  wrought  by  these 
molluscan  pests,  still  the  destruction  of  small  boats  and  especially  of 
docks  and  piles,  particularly  in  the  tropical  and  subtropical  waters,  is 
often  a  serious  matter.  Various  preventive  methods  have  been  tried, 


J 


MOLLUSC  A  67 

such  as  soaking  the  wood  in  creosote  and  other  materials  but  they 
all  seem  to  give  only  temporary  relief.  In  the  case  of  docks  and 
wharves  the  difficulty  is  being  overcome,  in  many  places,  by  the  use 
of  concrete. 

The  cephalopods,  Figs.  46  and  460,  are  of  comparatively  little 
economic  importance.  The  squid  are  used  by  fishermen  for  bait  and 
are  an  important  food  for  fishes.  The  rough  white  cuttle  bone  is 
used  in  bird  cages,  and  the  well-known  pigment,  sepia,  is  made  from 
the  ink  of  certain  cephalopods,  Sepia  in  particular. 

The  Amphineura  and  the  Scaphopods  are  of  practically  no  economic 
importance  other  than  as  zoological  specimens. 


CHAPTER  IX 


ARTHROPODA 

This  is  a  very  large  phylum  of  usually  comparatively  small  animals; 
there  are  more  species  here  represented  than  in  all  the  other  phyla 
combined.  As  their  name  indicates,  they  are  characterized  as  the 
first  animals  yet  studied  that  have  regularly  jointed  appendages. 
They  are  like  the  annelids  in  being  segmented,  in  having  a  mouth  at 
one  end  and  anus  at  the  other;  and  in  having  a  dorsal  brain  and  a 

ventral,  ganglionated  nerve  cord. 
They  usually  have  striated  muscle 
fibres,  and  are  almost  always  lacking 
in  cilia.  -The  body  cavity  is  largely 
represented  by  blood  sinuses  in  free 
communication  with  the  vascular 
system.  The  classification  is  exten- 
sive but  the  most  important  classes 
are  as  follows: 

I.  Crustacea,  Figs.  49,  50,  51,  53, 
54  and  55.  These  are  arthropods  in 
which  four  or  five  anterior  segments 
are  fused  to  form  the  head,  while  the 
rest  of  the  segments  may  usually  be 
divided  into  two  regions,  the  thorax 

ist  antenna;  a2,  2d  an-  and  the  abdomen.  Some  of  the 
thoracic  segments  may  be  fused  with 
the  head  to  form  a  cephalothorax,  as 
in  the  crayfish.  The  head  bears  a 

pair  of  compound  eyes,  sometimes  a  median  eye.  The  thoracic  and 
abdominal  appendages  are  variously  modified  as  claws,  legs,  fins,  ac- 
cessory reproductive  organs,  etc.;  the  typical  appendage  is  biramous: 
the  body  is  covered  with  a  variously  modified  exoskeleton  of  chitin. 
Respiration  is  by  means  of  gills  or  through  the  general  body  integument. 

68 


FIG.  49. — A  water  flea,  Cyclops. 
Xio. 

tenna;  e,  eye;  es,  egg  sac;  od,  ovi- 
duct; ov,  ovary;  t3,  3d  somite;  ui, 
uterus. 


ARTHROPODA 


69 


The  circulatory  organs  consist  of  a  contractile  heart,  a  series  of 
arteries  and  afferent  sinuses  and  veins.  The  excretory  organs  are 
modified  nephridia  known  as  shell  glands  or  green  glands,  located  in 
and  opening  from  the  anterior  part  of  the  body.  The  nervous  system 
consists  of  the  brain,  united  by  the  circumoesophageal  connectives  with 
'the  ventral,  ganglionated  nerve  cord.  Sexes  are  separate  or  united; 
parthenogenesis  is  common. 

The  class  is  divided  into  two  subclasses,  the  Entomostraca  and  the 
Malacostraca.  The  former  includes  the  smaller,  simpler  types,  such  as 
water  fleas,  barnacles,  etc.,  Figs.  49,  50,  and  51;  the  latter  includes  the 
larger,  more  highly  organized  forms  such  as  crayfish,  crabs,  lobsters, 
etc.,  some  of  which  may  be  several  feet  in  extreme  length,  Figs.  53 
and  54. 


FIG.  50. — Goose  barnacle,  Lepas  sp.      xM» 

II.  Onychophora,  Fig.  52.     This  class  includes  the  curious  cater- 
pillar, like  genus,  Peripatus,  which  is  interesting  as  having  character- 
istics of  both  the  Arthropods  and  the  Annelids — a  sort  of  "  connecting 
type." 

III.  Myriapoda,  Figs.  56,  57  and  58.     These  are  the  centipedes  and 
millipedes.     They  have   many  of  the  characteristics  of  the  insects. 
There  is  a  distinct  head,  bearing  jointed  antennae;  a  pair  of  eyes  and  two 
or  three  pairs  of  jaws.     The  rest  of  the  body  is  not  marked  off  into 
different  regions,  but  is  divided  into  many  segments,  which  in  some 
species  bear  a  single  pair  of  appendages  each  (centipedes)  and  in  other 
cases  two  pairs  of  appendages  each  (millipedes).     They  breathe  by  a 
system  of  trachea,  like  those  of  insects,  opening  to  the  exterior  through 
stigmata  on  the  lateral  or  ventral  side  of  the  body. 

IV.  Insects. — These  are  the  grasshoppers,  bees,  flies,  beetles,  butter- 
flies, dragon-flies,  etc.     It  is  the  largest  of  all  the  groups  of  animals, 


7O  ECONOMIC   ZOOLOGY 

both  in  number  of  species  and,  possibly,  in  the  number  of  individuals, 
with  the  probable  exception  of  the  Protozoa.  In  some  ways  the  insects 
are  the  most  highly  organized  of  the  invertebrates,  and  exhibit  an  in- 
telligence far  superior  to  that  of  many  of  the  lower  vertebrates. 

It  is  a  very  distinctive  group,  without  the  wide  variations  in  struc- 
ture seen,  for  example,  among  the  Crustacea;  their  name  "Hexapod" 


FIG.   51. — Acorn  barnacle,  Balanus  sp.      Xi. 

indicates  one  of  their  most  marked  characteristics,  the  invariable  pos- 
session of  six  legs,  born  on  the  thorax.  There  are  usually  two  pairs  of 
wings,  also  born  on  the  thorax.  The  body  is  distinctly  divided  into 
three  regions,  head,  thorax  and  abdomen.  The  respiratory  organs  are 
branching  air-tubes,  or  trachea,  extending  all  through  the  body.  The 


FIG.   52. — Peripatus     capensis,     drawn     from     life.     Somewhat     enlarged.      (From 
Hegner,  College  Zoology,  after  Sedgwick.) 

eggs  usually  hatch  into  a  grub  or  caterpillar,  and  undergo  a  marked 
metamorphosis  in  development  to  the  adult  condition.  The  adult  is 
terrestrial  or  aerial,  less  often  aquatic,  but  the  larval  stages  of  many 
forms  are  strictly  aquatic.  Some  forms,  bees,  ants,  etc.;  form  complex 
communities,  with  marked  polymorphism. 

V.  Arachnida,  Figs.   59  to  63.     This  rather  heterogeneous  class 
includes  the  spiders,  scorpions,  mites,  ticks,  king-crabs,  etc.;  though  the 


ARTHROPOD  A  71 

classification  of  some  of  these  is  uncertain.  There  is  usually  a  cephalo- 
thorax  and  an  abdomen;  in  some  cases  these  two  regions  are  fused. 
There  are  no  antennae  in  the  adult.  The  cephalothorax  bears  sessile 
and  usually  simple  eyes.  The  first  pair  of  cephalo thoracic  appendages 
are  the  chelicerae;  the  second  pair  are  the  pedipalpi;  posterior  to  these 
are  four  pairs  of  legs.  The  respiratory  organs  are  sometimes  trachea, 
sometimes  book-lungs,  sometimes  leaf-like  external  gills.  The  sexes 
are  usually  separate  and  there  is  no  metamorphosis. 

Crustacea. — The  American  lobster,  Homarus  americanus.  This  is 
probably  the  most  important  of  our  Crustacea.  As  a  laboratory  form 
it  is  now  rather  expensive  for  large  classes,  but  since  the  crayfish,  Fig. 
53,  is  almost  an  exact  anatomical  copy  of  Homarus,  on  a  small  scale, 
it  is  usually  used  for  dissection  purposes. 

The  Atlantic  Coast  of  North  America  is  the  greatest  lobster 
ground  in  the  world,  though  the  lobster  industry  of  western  Europe 
is  also  important.  The  species  under  discussion  is  found  from  Labrador 
to  North  Carolina,  but  it  is  exceedingly  rare  toward  the  southern 
limit  of  its  range;  Maine  and  Massachusetts  are  the  centre  of  the  lobster 
industry.  The  Pilgrims  found  the  Indians  using  the  lobster  for  food 
and  ever  since  that  time  it  has  been  one  of  our  most  highly  prized 
sea-foods.  It  is  said  the  Pilgrims  paid  their  debts  in  England  from  the 
products  of  their  fisheries. 

Like  so  many  of  the  natural  resources  of  the  country,  all  the  natural 
lobster  beds  of  the  Atlantic  are  now  more  or  less  depleted  and  the 
price  of  lobsters  has  risen  accordingly;  a  lobster  that  could  be  bought, 
a  generation  ago,  for  5  cents  will  now  bring  a  dollar  or  more.  In 
Canada  alone  100,000,000  lobsters  have  been  caught  in  a  year.  The 
total  catch  in  the  United  States  in  1892  was  about  23^  million  pounds; 
in  1905  it  was  about  nJ4  million  pounds,  which  sold  for  more  money 
than  the  catch  of  1892. 

Some  of  the  older  accounts  described  monster  lobsters  that  were 
"5  or  6  feet  long,"  this  probably  meant  with  the  claws  extended 
straight  in  front  of  the  head,  which  about  doubles  the  length  as  now 
measured  from  the  tip  of  rostrum  to  tip  of  tail.  The  largest  authentic 
measurements  that  we  have  give  a  length,  from  rostrum  to  tail,  of 
23/x4  inches,  and  a  weight  of  34  pounds.  As  a  medium-sized  lobster 
weighs  only  five  or  six  pounds,  it  will  be  seen  that  this  34-pound  speci- 
men was  a  monster.  The  European  lobster,  Homarus  gammarus, 


72  ECONOMIC   ZOOLOGY 

which  is  very  similar  to  the  American  form,  is  said  to  be  lighter  in 
proportion  to  its  length  than  the  latter  form. 

As  to  the  age  to  which  lobsters  live  we  have  but  little  data,  Herrick 
(97)  thinks  one  of  the  giant  lobsters  may  be  half  a  century  old.  A 
lo-inch  female  may  be  five  years  or  more  old.  As  in  the  crayfish 
the  female  lobster  carries  at  certain  seasons,  a  great  mass  of  eggs 
with  her,  glued  to  the  swimmerets  on  the  ventral  surface  of  the  ab- 
domen by  a  secretion  of  the  oviducts,  such  a  female  is  known  as 
a  uberried"  lobster  and  may  carry  10,000  or  more  eggs.  These  eggs  are 
carried  until  they  hatch  into  tiny  embryos  that  swim  to  the  surface  and 
look  quite  different  from  the  adult  lobster.  After  a  long  series  of  molts 
the  growing  lobsters  gradually  take  on  the  adult  form  and  sink  to  the 
bottom  where  they  live.  This  process  of  molting  is  general  among  the 
Crustacea.  Being  inclosed  in  an  inelastic  chitinous  exoskeleton  the 
lobster  can  grow  only  by  periodically  shedding  this  exoskeleton  and  then 
expanding  rapidly  before  the  new  exoskeleton  hardens;  the  growth  at 
one  molt  is  sometimes  surprisingly  great.  Molting  among  the  adults 
is  most  common  in  the  late  summer  and  early  fall.  The  process 
may  take  from  5  to  30  minutes  or  longer  and  it  is  generally  five  or 
six  weeks  before  the  new  shell  is  thoroughly  hardened.  The  Amer- 
ican lobster  breeds  biannually,  though  it  is  possible  that  annual  broods 
may  sometimes  be  produced. 

On  land  the  lobster,  owing  to  its  weight  and  relatively  weak  legs 
is  almost  helpless,  but  in  water  it  crawls  about  actively  on  the  bottom 
and  swims  backward,  by  flopping  its  tail,  at  a  remarkable  rapid  rate; 
one  specimen  was  seen  to  swim  25  feet  in  less  than  one  second.  Varia- 
tions of  temperature,  food  supply,  etc.,  cause  the  lobster  to  migrate 
from  shallower  to  deeper  water  and  back,  and  even  to  travel  along  the 
coast  for  some  miles.  It  may  hide  itself  beneath  rocks  and  such  things 
or  even  dig  a  burrow  in  the  mud,  somewhat  after  the  manner  of  the 
crayfish.  It  is  carnivorous  in  habits  and  feeds  most  actively  during 
the  warmer  seasons. 

In  the  early  days  the  Indians  caught  lobsters  by  spearing  them. 
In  Europe  they  were  caught  by  means  of  long  wooden  tongs.  The 
method  universally  employed  at  present  is  by  the  use  of  traps  or 
"pots, "  built  on  the  plan  of  the  typical  rat-trap,  with  a  conical  entrance 
at  one  or  both  ends.  Traps  of  this  sort  have  been  used  in  Europe  for 
centuries,  being  known  in  Scotland  as  "lobster  creels."  They  were 


ARTHROPOD A 


73 


formerly  of  the  wicker  basket  type,  but  are  now  usually  made  of  lath. 
They  may  be  rectangular,  cylindrical  or  semicylindrical,  and  are  from 
2j^  to  4  feet  long,  about  2  feet  wide  and  i  J^  feet  high.  The  ends  are 
of  heavy  mesh  in  the  form  of  an  inverted  cone  with  an  entrance  hole 
about  6  inches  in  diameter,  so  that  the  lobster  can  easily  crawl  in  but 
cannot  readily  find  its  way  out  again.  The  slats  are  nailed  about 
2  inches  apart  on  some  sort  of  frame  and  have  a  door  in  the  top 
through  which  the  lobsters  may  be  removed. 

The  traps  are  baited  with  herring,  halibut,  fish-heads,  etc.;  they 
are  sunk  to  the  bottom  with  stones  or  other  weights  and  are  secured 
with  a  rope  long  enough  to  reach  the  surface  of  the  water  where  it  is 
attached  to  a  wooden  buoy,  painted  with  the  owner's  name  or  color. 
The  traps  are  usually  set  at  a  short  distance  from  the  shore,  usually  in 
i  to  10  fathoms  of  water  in  summer,  but  in  winter  they  may  be  out  5 
or  6  miles,  in  25  to  50  fathoms.  The  traps  are  pulled  as  often  as  once 
or  twice  a  day  in  summer,  but  in  stormy  winter  weather,  a  week  or  two 
may  pass  before  they  can  be  visited;  many  are  lost  in  winter  storms. 
After  removal  from  the  traps  the  lobsters  may  be  kept  in  live  boxes  until 
ready  for  shipment,  which  is  done  by  packing  them  in  wet  sea-weed, 
with  ice  below  them  in  warm  weather;  the  ice  must  be  beneath  as  the 
dipping  of  the  fresh  water  from  the  melting  ice  is  fatal;  the  claws  may 
be  plugged  or  tied  to  prevent  their  being  used.  In  this  condition 
they  may  be  shipped  almost  any  reasonable  distance.  The  longest 
distance  they  have  been  shipped  was  from  England  to  New  Zealand, 
about  12,000  miles;  several  such  shipments  have  been  made  with 
comparatively  little  loss  of  life;  each  lobster  in  this  case,  however,  was 
put  into  a  separate  wooden  compartment  with  clear,  cool,  aerated  water 
and  was  fed  during  the  journey,  which  lasted,  in  one  case,  54  days. 

Several  lots  of  American  lobsters  have  been  transported  across 
the  continent  and  planted  along  the  Pacific  Coast  from  Monterey 
Bay  to  Puget  Sound;  while  no  definite  results  seem  yet  to  have  been 
attained  it  is  probable  that  the  experiment  will  eventually  prove 
successful. 

When  the  supply  of  lobsters  became  seriously  diminished  means 
were  sought  to  aid  nature  to  replenish  the  waters  that  had  been  so 
thoughtlessly  robbed. 

The  most  obvious  thing  to  do  was  to  strip  the  eggs  from  the  berried 
lobsters  and  carry  them  through  the  earlier  stages  of  their  development 


74  ECONOMIC   ZOOLOGY 

in  the  safety  of  hatching  jars.  This  is  now  done  at  numerous  hatcheries 
along  the  coast,  one  of  the  largest  of  which  is  at  Boothbay  Harbor, 
Maine.  The  eggs  after  being  carefully  scraped  from  the  swimmerets 
of  the  female  are  put  into  glass  jars  where  they  are  kept  in  running  water 
and  carefully  tended  until  they  hatch  and,  preferably,  have  reached 
the  bottom-seeking  stage,  when  they  are  taken  out  to  sea  and  liberated 
at  favorable  localities  along  the  coast.  Many  millions  of  such  young 
lobsters  are  liberated  each  season. 

Besides  this  rearing  of  young,  other  expedients  are  recommended  and 
are  being  applied  in  some  regions,  as  follows: 

1.  Have  a  standard  trap  with  an  entrance  too  small  to  admit  the 
largest  lobsters,  which  are  thus  saved  for  breeders,  and  with  slats  so 
far  apart  that  lobsters  less  than  10  inches  in  length  can  escape. 

2.  License  every  lobster  fisherman. 

3.  Protect  the  berried  lobsters  by  forbidding  their  sale,  and  offer  a 
bounty  upon  them  at  the  hatcheries  where  they  may  be  stripped.     This 
bounty  will  tend  to   prevent  dishonest  fishermen  from  stripping  the 
females  and  then  selling  them  in  the  open  markets. 

4.  Abolish  the  closed  season  and  permit  fishing  throughout  the  year. 
Spiny  lobsters,  genus  Palinurus.     These  lobsters  which  are   often 

large  and  spiny  but  are  without  claws  are  found  in  various  parts  of  the 
world.  P.  vulgaris,  the  common  spiny  or  rock  lobster  is  common  in 
southern  and  western  Europe  and  is  an  important  article  of  food. 
It's  meat  is  largely  confined  to  the  thorax  and  abdomen  and  is  said  to 
be  as  delicious  as  that  of  the  true  lobsters. 

P.  interruptus  is  found  on  the  western  coast  of  North  America  and 
often  reaches  a  considerable  size. 

Crayfish,  or  Crawfish, genus  Cambarus  (eastern  U.  S.)  and  Astacus 
(Europe  and  Pacific  coast  of  U.  S.),  Fig.  53.  These  two  genera,  of 
which  there  are  many  species,  have  a  greater  economic  importance, 
both  positive  and  negative,  than  is  commonly  realized.  The  positive 
side  will  first  be  briefly  discussed. 

For  many  years  they  have  been  so  extensively  used  as  food  in 
European  countries  that  it  has  been  profitable  to  rear  them  artificially. 
Their  use  in  the  U.  S.,  though  not  so  general,  is  increasing;  for  example, 
16,000  pounds  of  Cambarus  were  sold  from  New  Orleans  Co.,  La., 
in  a  year,  and  over  55,000  pounds  from  Monroe  Co.,  Fla.  On  the 
Pacific  coast  the  larger  genus,  Astacus,  is  collected  in  large  numbers, 


ARTHROPOD A 


75 


165,000  pounds  being  sold  in  Oregon  in  one  year;  these  are  prepared 
for  shipment  by  placing  them  alive  in  white  wine  and  spices,  and  boiling 
for  two  minutes;  they  are  then  shipped  in  this  liquid  in  tin  containers. 
The  Astacus  is  not  only  larger  but  has  larger  claws  and  is  more 
lobster-like  than  Cambarus,  hence  it  brings  better  prices.  It  could 
doubtless  be  introduced  into  the  east.  The  eggs  are  laid  in  the 
spring  and  the  animal  becomes  sexually  mature  the  following  spring 
and  reaches  its  full  size  in  three  or  four  years  though  these  figures 
may  vary  considerably  in  different  species  and  under  different  con- 
ditions. They  can  be  easily  raised  in  ponds,  requiring  merely  air, 
fresh  water  and  some  sort  of  organic  food;  refuse  animal  and  vegetable 
matter  may  be  used. 


FIG.  53. — Crayfish,  Cambarus  sp.      X^t- 

The  damage  done  by  crayfish,  in  certain  sections,  is  very  consider- 
able, especially  in  the  clay  lands  of  Alabama  and  Mississippi.  The 
crayfish  often  dig  holes  into  the  ground  to  a  depth  of  several  feet, 
with  the  excavated  earth  piled  in  a  circular  chimney  at  the  orifice. 
In  these  clay  lands  the  bottoms  of  the  holes  are  always  filled  with  water, 
making  ideal  homes  for  the  animals.  In  an  area  of  about  1000  square 
miles  the  crayfish  very  largely  prevent  the  successful  raising  of  cotton 
and  corn.  They  damage  the  young  plants  just  after  they  appear, 
generally  by  tearing  off  the  tender  cotyledons. 

The  number  of  crawfish  in  some  of  the  infested  areas  may  be  seen 
from  the  fact  that  there  may  be  8000  to  12,000  holes  to  the  acre, 
and  on  one  plantation  27  barrels  of  crayfish  were  collected  in  a  season, 


76  ECONOMIC   ZOOLOGY 

It  is  sometimes  the  custom  to  pay  negroes  a  barrel  of  flour  or  of  corn 
for  each  barrel  of  crayfish  collected.  The  Department  of  Agriculture 
investigated  the  problem  and  found  various  remedies.  Apparently 
if  they  are  persistently  hunted  at  twilight,  at  night,  or  after  a  rain, 
they  may  be  exterminated  or  so  reduced  in  numbers  as  to  be  of  little 
harm.  The  easiest  way  is  to  pass  along  the  rows  and  systemati- 
cally kill  them  with  clubs  or  by  stepping  on  them.  If  instead  of  this, 
they  be  collected,  they  may  be  either  sold  as  food  for  man  or  they  may 
be  boiled,  mixed  with  meal,  and  allowed  to  dry,  when  they  make  most 
excellent  chicken  feed. 

There  are  various  poisons  that  when  introduced  into  the  holes 
and  then  filled  in,  will  destroy  the  animals  and  leave  them  buried. 
Chlorid  of  lime,  (one  pound  to  three  gallons  of  water)  is  effective 
and  cheap,  but  the  mixing  and  hauling  may  make  it  as  expensive 
as  carbon  bisulphid,  which  may  be  introduced  into  the  hole  with 
a  long  oil  can,  such  as  locomotive  engineers  use,  after  which  the  hole 
is  closed  by  stepping  on  it.  The  cost  of  the  carbon  bisulphid  will 
be  from  $i  to  $2  per  acre,  or  perhaps  more  in  times  of  high  prices,  and 
the  cost  of  the  labor  will  perhaps  be  greater  than  the  cost  of  the  poison. 

Crabs. — There  are  many  kinds  of  crabs  that  are  used  for  food  by 
man.  In  the  tropics  several  forms  of  land  crabs  are  thus  used,  some  of 
them  being  collected  in  large  numbers  as  they  migrate  from  the 
mountains  to  the  sea  to  spawn. 

In  the  United  States  it  is  the  strictly  aquatic  forms,  Callinectes 
and  others,  that  are  used,  Fig.  54.  These  are  used  both  as  "hard- 
shell" and  as  "soft-shell"  crabs;  the  former  is  the  crab  in  its  normal 
condition  with  the  hard,  chitinous  exoskeleton;  the  latter  is  simply 
a  crab  that  has  recently  molted,  whose  exoskeleton  has  not  yet 
hardened.  The  hard-shell  crab  is  caught  either  in  traps,  like  those 
used  for  lobsters,  or  on  lines  baited  with  stale  meat,  the  entrails  of 
fowls,  etc.  No  hook  is  used  in  "crabbing;"  the  crabber  simply  sup- 
plies himself  with  the  necessary  bait,  with  a  dip-net  and  with  a  quantity 
of  cheap  twine.  The  twine  is  cut  into  suitable  lengths  and  is  tied 
to  pieces  of  bait  and  the  latter  hung  into  the  water  from  the  side  of 
the  boat  or  dock,  or  at  intervals  along  a  long  "trot  line. "  The  fisher- 
man goes  from  string  to  string  and  pulls  each  up  slowly  until  the  bait 
is  near  the  surface  of  the  water,  when,  with  a  quick  dip  of  the  net, 
he  captures  the  crab  or  crabs  that  may  be  clinging  to  the  meat  with 


ARTHROPODA 


77 


their  claws.  The  crabs  will  drop  off  if  the  bait  be  raised  out  of  the 
water.  Sometimes  two  or  three  or  even  more  crabs  will  be  taken 
with  one  sweep  of  the  net.  With  a  dozen  or  less  lines  one  person  may 
keep  continually  at  work  and  if  the  crabbing  be  good  he  will  soon 
have  more  than  he  can  carry  home.  The  soft-shell  crab  does  not  allow 
itself  to  be  thus  easily  captured,  and  hence  is  more  of  a  luxury.  Being 
unprotected  with  a  hard  shell  it  seeks  safety  by  hiding  itself  under  the 
sea-grass,  etc.,  at  the  bottom,  where  it  must  be  sought  with  a  long 
handled  net  or  by  wading  along  the  shore  where  the  water  is  shallow. 


FIG.  54. — Common  rock  crab,  Cancer  irroratus.      x%. 

The  hard-shell  crab  is  usually  cooked  by  throwing  it  alive  into  boil- 
ing water,  after  which  the  meat,  with  the  exception  of  certain  parts,  is 
picked  out,  seasoned  and  then  baked,  either  in  cakes  or  in  the  cleaned 
shells  of  the  crab;  such  "deviled"  crabs  are  very  common  in  all  parts  of 
the  country  that  are  at  all  accessible  to  the  coast.  The  soft-shell  crabs 
do  not  have  to  be  removed  from  their  shells,  but  are  eaten  shell  and  all. 
Like  some  other  sea-foods,  crab  meat,  unless  carefully  prepared,  quickly 
spoils  and  causes  violent  sickness. 

Like  our  other  supposedly  inexhaustible  resources,  the  crabs  have 
begun  to  become  scarce,  so  that  certain  laws  as  to  size,  closed  seasons, 
berried  crabs,  licenses  for  fishermen,  etc.,  have  been  passed  to  protect 
this  important  industry  before  it  is  too  late. 


78 


ECONOMIC   ZOOLOGY 


Shrimps  and  Prawns,  Fig.  55,  are  usually  small  Crustacea,  of  several 
species,  found  in  various  parts  of  the  world.  They  are  used  in  this 
country  mainly  for  salads,  and  look  like  small,  soft  crayfish.  In  the 
tropics,  the  natives  are  often  seen  wading  about  in  the  shallow  waters 
with  a  hand  net  that  they  sweep  through  the  aquatic  grasses,  to  collect 
these  small  (sometimes  not  over  an  inch  long)  Crustacea  that  are  dried 


FIG.   55. — A  shrimp,  Palaemon  sp.      X%. 

in  the  sun  and  taken  to  market.  In  many  parts  of  Europe  they  are  ex- 
tensively used  for  food.  In  cans  they  may  be  transported  any  distance 
and  will  keep  indefinitely,  and  it  is  in  this  condition  that  they  are  usually 
seen. 

Onychophora  and  Myriapoda.— These  two  classes  are  of  so  little 
economic  importance  that  they  may  be  dismissed  with  but  a  few  words. 


FIG.   56. — Centipede,  Scolopendra  sp.      X%. 

The  former  class  probably  has  no  economic  importance  other  than  its 
value  for  museum  and  scientific  purposes. 

The  centipedes,  belonging  to  the  latter  class,  are  said  to  be  eaten 
by  the  South  American  Indians.  The  myriapods  are  very  generally 
feared  though  most  of  them  are  quite  harmless.  The  large  tropical  cen- 
tipedes, genus  Scolopendra,  Fig.  56,  are  poisonous  to  man,  possibly 
fatally  so  at  times;  they  may  reach  a  length  of  18  inches.  The  well- 


ARTHROPOD A  79 

known  house  centipede,  Scutigera  forceps.  Fig.  57,  is  supposed  by  many 
to  be  very  poisonous  and,  according  to  Marlatt,  it  has  a  decidedly 
disagreeable  bite,  which  may  be  alleviated  by  the  prompt  application 
of  ammonia;  it  feeds  on  roaches,  flies  and  other  insects,  probably  in- 
cluding bedbugs,  so  that  it  is  a  useful  animal  except  for  its  poisonous 
bite. 


PiG.   57. — House   centipede,    Scutigera  forceps.       X/3-      (From   Marlatt,  The  House 

Centipede.) 

The  millipedes,  Julus  and  others,  Fig.  58,  are  harmless  to  man 
but  are  often  destructive  to  crops. 

Arachnida. — The  economic  importance  of  this  group,  which  includes 
some  animals  of  great  zoological  interest,  is  not  great  and  is  very  largely 
negative. 

Spiders,  Figs.  59  and  60.  Some  of  the  web-building  spiders  have  a 
slight  positive  importance  from  the  fact  that  the  fine  threads  that  they 


FIG.   58. — A  milliped,  Julus.      X%. 

spin  may  be  wound  upon  a  reel  and  used  for  the  cross-hairs  of  surveying 
and  other  instruments  of  precision.  They  are  also  of  some  value  as 
destroyers  of  insects.  Popularly  the  spiders  are,  as  a  group,  supposed 
to  be  poisonous,  even  dangerously  so.  Students  of  spiders,  however, 
have  generally  maintained  that,  with  the  exception  of  the  huge,  hairy 
tarantulas  of  warm  climates,  the  North  American  spiders  are  harmless. 
Recently  Kellogg  (102)  has  pointed  out  that  the  notorious  black  widow 


8o 


ECONOMIC   ZOOLOGY 


spider,  Latrodectus  mactans,  Fig.  60,  really  is  at  times,  dangerously 
poisonous  to  man.  Latrodectus  is  widely  distributed  over  the  earth 
and  is  generally  feared.  In  the  Americas  there  are  three  species  of  this 
genus,  the  best  known  being  the  one  named  above,  which  is  found  from 
the  northern  part  of  the  United  States  to  the  southern  end  of  South 
America,  it  is  common  in  our  southern  and  southwestern  states.  The 
male  has  an  elliptical  abdomen  and  is  about  12  mm.  in  length.  It  is 
a  "sooty-black  or  dark  brown  color  with  a  conspicuous  small  blotch 

or  blotches  of  vivid  red  on  the  under  side 
of  the  abdomen.  This  blotch  or  pair  of 
fusing  blotches  has  the  rough  outline  of 
an  hour-glass.  However  it  varies  much 
in  shape."  The  position  and  vivid  color 
of  this  spot  on  the  dark  body  are  char- 
acteristic. 

Kellogg  discribes  a  case  in  California 
in  which  most  serious  results  followed 
the  bite  of  this  spider.  Enormous  swell- 
ing of  the  bitten  organ,  intense  pains 
with  cramp,  labored  respiration,  slowed 
heart-beat,  etc.,  were  noted.  A  cat  in- 
jected with  an  attenuated  dose  of  the 
poison  died  in  10  minutes,  other  animals 
reacted  strongly. 


FIG.   59. — "Tarantula" 
spider,  sp.       X^3- 


"A  diadem  spider  of  1.4  gr.  (weight), 
contains  sufficient  poison  to  destroy  com- 
pletely all  the  corpuscles  in  2.5  liters  of 
rabbit's  blood." 


Doubtless  the  effects  of  the  bite  of  these  spiders  are  more  marked 
with  some  persons  than  with  others  and  with  the  same  person  at  dif- 
ferent times.  Kobert  says  they  may  "produce  by  their  bite  the  most 
serious  general  results,  and  are  capable  of  killing  even  men."  The  bite 
of  the  Tarantula  may  often  be  painful  without  being  serious. 

Of  poisonous  spiders  Comstock  (93)  says:  "The  so-called  Tar- 
antula (Heteropoda)  that  is  frequently  brought  to  the  North  in 
bunches  of  bananas  is  often  described  as  the  cause  of  serious  injury. 
This  however,  though  a  large  spider,  is  an  inoffensive  one.  Mr. 


ARTHROPOD A 


8l 


John  T.  Lloyd  informs  me  that  he  has  collected  scores  of  specimens  of 
this  species  with  his  hands  in  Samoa,  where  it  is  abundant,  and  has 
never  been  bitten  by  it. 


A  c 

FIG.  60. — A,   black  widow  spider,  Latrodectus  mactans,  female.      X3-     B>  ventral 
view  of  same;  C,  body  of  male.      X3-     (From  Comstock,  The  Spider  Book.) 

"Although  we  have  in  the  North  no  spider  that  is  to  be  feared,  it 
is  quite  possible  that  in  the  South  it  is  different.  I  confess  that  I  should 
not  like  to  be  bitten  by  one  of  the  larger  Tarantulas  of  that  region, 
although  I  know  of  no  well-authenticated  case  of  a  person  being  bitten 
by  one. 


82 


ECONOMIC   ZOOLOGY 


"The  spiders  of  the  genus  Latrodectus,  of  which  we  have  a  common 
representative  in  the  South,  are  feared  wherever  they  occur,  and  it  is 
quite  possible  they  are  more  venomous  than  other  spiders." 

Scorpions,  Fig.  61.     These  curious  and  dreaded  animals  with  the 
"sting"  at  the  end  of  the  tail  are  often  abundant  in  tropical  and  sub- 
tropical countries.     The  sting  of  a  large  zo-inch  specimen  may  be  seri- 
ous; that  of  an  ordinary  3-  or  4-inch   animal  is 
usually  about  as  severe  as  the  sting  of  a  wasp  or 
hornet. 

There  are  several  small  arachnids,  of  the 
order  Acarina,  that  are  external  parasites  on 
man  and  other  animals  and  are  sometimes  a 
serious  pest.  For  example,  the  tiny  harvest- 
mites  or  chiggers  burrow  into  the  skin  of  man 
and  cause  most  annoying  itching;  they  may  be 
killed  by  rubbing  the  skin  with  kerosene,  a  i 
per  cent,  solution  of  carbolic  acid,  or  other 
similar  substance. 

Poultry  and  cattle  ticks,  Fig.  62,  cause  in- 
jury to  their  hosts,  the  latter  in  particular  as  a 
carrier  of  the  germ  of  the  Texas  cattle  fever,  as 
described  in  connection  with  the  Protozoa. 

The  follicle  mites,  Fig.  62,  C,  live  in  the  hair 
follicles  and  sweat-ducts  of  man  and  cause 
"blackheads;"  the  itch-mite,  Fig.  62,  D,  by 
burrowing  in  the  skin  produces  intense  itching, 
and  the  sheep-scab  mite  produces  scabs  on  the 
skin  of  sheep,  cattle  and  horses. 

King-crab  or  horse-shoe  crab,  Limulus,  Fig.  63.  This  is  perhaps 
the  largest  of  living  arachnids,  reaching  an  extreme  length  of  2  feet. 
It  is  one  of  the  few  members  of  this  class  that  live  in  the  sea,  where  it 
is  found  crawling  or  slowly  swmiming  over  the  sand  or  mud  flats  along 
shore.  It  is  interesting  zoologically  and  is  said  to  be  fairly  good  as 
food,  though  it  is  not  very  commonly  eaten.  It  is  sometimes  classed 
with  the  Crustacea,  as  its  affinities  are  uncertain.  Along  the  shores 
of  Delaware  Bay  it  is  caught  by  the  ton,  as  it  comes  ashore  to  spawn; 
it  is  used  as  food  for  hogs  and  as  a  fertilizer. 


FIG.      61. — Scorpion, 
Centrums  sp.    X%. 


ARTHROPOD A 


Insecta. — There  are  more  species  of  insects  known  than  of  all  the 
other  groups  of  animals  combined.  Their  numbers,  though  variously 
estimated,  run  well  up  in  the  hundreds  of  thousands,  and  the  number 
of  undescribed  species  can  hardly  be  estimated.  The  study  of  this 
enormous  class  is  a  large  department  of  science  in  itself,  Entomology, 
and  one  of  great  importance  largely  because,  as  a  class,  insects  are 
highly  destructive  to  vegetation  and  injurious  to  man  in  other  ways. 

It  has  been  estimated  that  the  direct  annual  loss  in  the  United  States 
due  to  insects  is  about  one  billion  dollars,  besides  the  losses  due  to  dis- 
ease-producing and  other  noxious  forms. 


D  E 

PIG.  62. — Acarina,  enlarged.  C,  follicle  mite,  Demodex  folliculorum.  D, 
itch  mite,  Sarcoptes  scapici.  E,  sheep-scab  mite,  Psoroptes  communis  var.  avis. 
(From  Hegner,  College  Zoology,  C  and  D,  after  Sedgwick,  C,  from  Mengin,  D,  from 
Gudden,  E,  from  Osborn.) 

The  relation  of  insects  to  agriculture  is  too  large  a  subject  to  even 
touch  upon  in  a  book  like  this;  there  are  whole  libraries  of  entomology 
dealing  with  this  phase  of  economic  zoology.  It  may  be  interesting, 
however,  to  briefly  discuss  a  few  insects  that  are  harmful  to  man  in 
other  ways,  and  a  few  that  are  highly  beneficial. 

Mosquitoes. — The  part  played  by  mosquitoes  in  the  transmssion 
to  man  of  malaria,  yellow  fever,  etc.,  has  already  been  noted  in  Chapter 
I.  Though  to  most  people  all  mosquitoes  "look  alike"  there  are  sev- 
eral hundred  species,  and  according  to  Felt  (95)  there  are  50  or  more 
species  in  New  York  State.  Of  these,  two  or  three  genera,  have  al- 
ready been  mentioned;  Culex,  the  common  non-malarial  forms;  Ano- 
pheles, the  malarial  mosquito;  and Stegomyia,  the  yellow-fever  mosquito. 
The  last  named  is  ordinarily  found  only  in  tropical  or  sub-tropical 


84 


ECONOMIC   ZOOLOGY 


regions,  and  is  nearly  always  found  in  or  about  houses.     It  is  sometimes 

called  the  "day  mosquito"  from  its  habit  of  biting  in  the  daytime. 

This  mosquito,  Fig.  64,  is  black  with  conspicuous  white  markings; 

the  legs  and  abdomen  are  banded  with  white,  while  the  thorax  is  marked 

with  white  in  the  form  of  a  lyre. 

Anopheles,  the  other  important  disease  carrier  may  be  distinguished 

from  the  non-malarial  forms  as  follows:  it  has  spotted  wings,  while  most 

of  the  other  forms  have  clear  wings; 
it  has  long  mouth  palpi,  shown  ven- 
tral to  the  proboscis  in  Fig.  65;  and 
when  at  rest  the  head  and  proboscis 
are  in  one  line  with  the  body  and 
form  a  considerable  angle  with  the 
surface,  instead  of  being  nearly 
parallel  to  it,  Fig.  65;  the  position 
of  the  breathing  larva,  close  to  the 
surface  of  the  water,  is  shown  in 
the  upper  half  of  Fig.  66. 

TAs  is  well  known  it  is  the  female 
mosquito  that  bites,  possibly  the 
male,  in  most  cases,  takes  no  food. 
The  males  may  often  be  recognized 
by  their  large,  feathery  antennae, 
which  have  given  them  the  name  of 
" woolly  heads."  It  is  commonly 
supposed  that  they  live  upon  blood, 
but  it  is  likely  that  not  one  in  a 
million  ever  tastes  blood;  their  natu- 
ral food  is  generally  the  juices  of 
soft  plants,  which  accounts  for  the  oenencial  results  of  cutting  down 
rank  vegetation  in  the  neighborhood  of  mosquito-infested  houses. 
They  may  be  kept  in  captivity  by  feeding  them  on  ripe  bananas. 

While  there  is  some  variation  in  the  life-histories  of  the  different 
species,  the  general  process  is  about  as  follows:  the  female  lays  a  number 
of  eggs, either  singly  or  in  masses  that  float  on  the  surface  of  the  water; 
there  may  be  several  hundred  eggs  in  one  of  these  masses  or  "rafts," 
Fig.  67.  The  water  may  be  fresh  or  salt,  clean  or  foul;  even  cess-pools 
or  wet  mud  may  serve  for  some  species.  The  water  may  be  a  lake, 


FIG.   63. — King  or  horse-shoe  crab, 
Limulus  Polyphemus.       X%. 


ARTHROPOD A 


or  it  may  be  a  few  ounces  in  an  upturned  tomato  can;  it  must,  however, 
be  still  or  the  female  cannot  light  upon  its  surface  to  deposit  her 
eggs,  hence  rapid  streams  do  not  breed  mosquitoes.  The  eggs  hatch, 
depending  on  the  species  and  upon  the  conditions,  as  soon  as  16  hours 
after  being  laid,  perhaps  even  sooner.  The  larvae,  Fig.  66  and  67, 


FIG.  64. — Yellow-fever    mosquito,    Stegomyia     calopus     (faciata). 
Insects  and  Diseases,  by  Neivstead.) 


(After    Doane, 


work  out  of  the  lower  side  of  the  eggs  and  begin  their  life  as  wrigglers, 
coming  to  the  surface  at  frequent  intervals  to  breathe  through  the  air- 
tube  near  the  end  of  the  tail;  this  larval  life  may  last  from  one  to  three 
or  more  weeks,  during  which  time  the  insect  molts  several  times  until 


86 


ECONOMIC   ZOOLOGY 


it  finally  reaches  the  pupa  stage,  Fig.  68,  when  it  stops  feeding  and 
lies  quietly  on  the  surface  of  the  water,  breathing  through  tubes  situ- 
ated on  the  dorsal  side  of  the  thorax,  instead  of  near  the  end  of  the  ab- 
domen. The  larva  is  heavier  than  water  and  has  to  wiggle  actively  to 
get  to  the  surface  to  breathe,  the  pupa  is  lighter  than  water  and  lies 
without  effort  at  the  surface.  The  pupal  stage  may  last  from  two  to 
six  days  or  more.  When  the  adult  is  ready  to  emerge  the  pupal  skin 
splits  down  the  back  and  the  mosquito  slowly  escapes;  it  may  take 


PIG.  65. — Resting  position  on  vertical  wall  of  Culex  (left)  and  Anopheles 
(right).  (From  Howard,  Mosquitoes  of  the  United  States,  after  the  British  Medical 
Journal.}  Enlarged. 

several  minutes  for  the  animal  to  issue  from  the  old  skin  and  for  its 
wings  to  dry  and  harden  enough  for  flight;  during  this  time  it  stands 
on  the  floating  pupa  skin  and  is,  of  course,  easily  upset  and  drowned 
by  the  least  roughness  of  the  surface  of  the  water;  this  is  another  reason 
why  mosquitoes  do  not  breed  in  running  water. 

How  long  the  adult  mosquito  lives  is  difficult  to  determine;  some  of 
them  hibernate  all  winter,  but  in  confinement  they  usually  die  rather 
soon. 

Some  species  fly  for  considerable  distances,  but,  as  a  rule,  they  re- 
main very  close  to  their  place  of  birth,  so  that  it  may  even  be  possible 


ARTHROPOD A  87 

to  rid  one  suburban  residence  of  the  pest  while  the  next  place  is  still 
infested.  They  are  delicate  creatures  and  seldom  attempt  to  fly  in 
a  strong  breeze,  but  a  very  gentle  breeze  may  carry  them  for  a  consider- 


PiG.  66. — Larva  of  Anopheles  in  feeding  and  breathing  position,  just  below 
the  surface  of  the  water  (upper  figure).  Larva  of  Culex  in  breathing  position, 
at  an  angle  to  the  surface  (lower  figure).  Enlarged.  (From  Howard,  Mosquitoes 
of  the  United  States.) 

able  distance.  They  are  often  carried  for  many  miles  in  railway  trains 
and  other  public  conveyances  to  regions  ordinarily  free  from  them. 
Knowing  their  breeding  habits,  the  methods  of  mosquito  control 
will  immediately  suggest  themselves;  the  first  is  to  destroy  all  breeding 
places;  this  may  mean  the  drainage  of  swamps  and  ponds  or  it  may  sim- 


88 


ECONOMIC   ZOOLOGY 


ply  mean  the  overturning  of  tin  cans,  tubs,  etc. ;  even  a  gutter  on  a  roof 
that  has  become  clogged  with  leaves  and  dirt  may  breed  mosquitoes  by 
the  thousand.  If  the  water  cannot  be  led  away  nor  poured  out  the 
problem  may  be  handled  in  other  ways;  ponds  that  cannot  be  drained 
may  be  sprayed  with  kerosene  or  crude  petroleum,  about  i  ounce  per 
15  square  feet  once  a  month  during  the  mosquito  season;  or  if  this  be 
impracticable  or  undesirable,  the  pond  may  be  stocked  with  minnows 
or  other  small  fish  that  will  feed  upon  the  larval  mosquitoes.  These 


FIG.  67. — Culex  pungens;  egg  mass,  with  more  enlarged  eggs  at  left;  young  larvee 
below.      Enlarged.     (From  Howard,  Mosquitoes  of  the  United  States.) 


small  fish  will  be  much  more  effective  if  the  sloping  banks  of  the  pond  be 
cut  away  so  that  the  larvae  may  not  escape  the  fish  by  going  into  the 
very  shallow  water  close  to  shore. 

Dragon  flies  are  excellent  mosquito  destroyers,  as  their  larvae 
eat  the  larval  mosquitoes  and  the  adults  catch  and  eat  the  adult  mos- 
quitoes. Rain  barrels,  and  cisterns  can  usually  be  screened  to  keep  out 
the  adult  mosquitoes  and  this  is  one  of  the  important  proceedings  in 
crusades  against  the  yellow  fever  mosquitoes  in  the  South. 

In  some  of  the  great  swamps  of  the  South,  the  extermination^  .qf 
mosquitoes  is  a  difficult,  if  not  impossible,  task;  but  in  most  localities 


ARTHROPOD A 


89 


a  pest  of  mosquitoes  is  a  reflection  upon  the  ownership  or  upon  the  local 
government. 

The  house-fly,  Musca  domestica,  Fig.  69.  An  even  more  serious  pest 
than  the  mosquitoes  are  the  flies,  the  house-fly,  in  particular.  This 
only  too  familiar  animal  has,  until  recent  years,  been  regarded  as  rather 


PIG.  68. — Culex    pungens;  full-grown    larva    at    left;    pupa    at    right. 
(From  Howard,  Mosquitoes  of  the  United  States.) 


Enlarged. 


an  innocent  little  nuisance  that  tickled  us  when  we  wanted  to  sleep, 
and  got  into  our  food.  That  this  idea  is  still  somewhat  prevalent  is 
seen  in  the  attitude  of  the  average  person  toward  flies  and  roaches; 
if  the  comparatively  harmless  roach  finds  its  way  into  our  soup  we  throw 


ECONOMIC   ZOOLOGY 


it  away  in  disgust,  but  many  a  housekeeper  will  fish  half  a  dozen  filthy 
flies  out  of  the  milk  pitcher  and  "shoo"  them  off  the  cake  without  a 
thought.  To  most  persons  "  all  flies  look  alike  "  and  they  do  not  realize 
the  number  of  species  that  are  a  pest  to  man  and  to  the  lower  animals. 


FIG.  69. — The  house-fly,  Musca  domestica.      (After  Doane,  Insects  and  Disease.) 

For  example,  the  sheep  bot-flies  lay  their  eggs  in  the  nostrils  of  sheep  and 
when  the  larvae  hatch  they  crawl  up  into  the  frontal  sinus  causing 
great  suffering  to  the  sheep  and  loss  to  the  owner. 

The  horse  bot-flies  lay  their  eggs  on  the  body  of  the  horse  and  when 


ARTHROPODA 


the  horse  licks  himself  the  eggs  get  into  his  alimentary  canal  where 
they  hatch  into  maggot-like  larvae. 

The  bot-fly  larvae  of  cattle,  the  ox  warbles,  get  into  the  alimentary 
canal  in  the  same  way,  but  instead  of  lodging  in  the  stomach  they  bur- 


FIG.    70. — Wing    of    stable-fly,    Stomoxys    calcitrans. 

Disease.) 


(After    Doane,    Insects    and 


row  out  through  the  esophagus  until  they  come  to  lie  under  the  skin 
of  the  back;  here  they  develop  and  make  ugly  sores,  and  when  mature 
they  cut  through  the  skin,  fall  to  the  ground  and  complete  their  develop- 


PIG.   71. — Wing  of  house-fly,  showing  adhering  dirt  in  which  bacteria  may  lodge. 
(After  Doane,  Insects  and  Disease.) 

ment.     The  holes  they  make  in  escaping  injure  or  even  ruin  the  skin  for 
leather. 

The  human  bot  or  screw-worm  flies  lay  their  eggs  in  sores  on  the 
body;  the  eggs  very  quickly  hatch  and  the  maggots  burrow  under  the 
skin  causing  painful  and  even  fatal  results. 


92  ECONOMIC   ZOOLOGY 

The  widely  prevalent  and  dangerous  disease  of  horses  and  cattle  in 
the  orient,  surra,  is  probably  conveyed  by  flies,  as  was  noted  before. 
Numerous  other  illustrations  of  the  injury  wrought  by  various  species 
of  flies  might  be  given. 

Anyone  will  recognize  the  difference  between  the  house-fly  and  the 
blue  bottle  fly  or  the  horse-fly  or,  perhaps,  even  between  it  and  the  simi- 
lar stable-fly.  Fig.  69  is  an  excellent  representation  of  the  house-fly, 
and  a  comparison  of  Figs.  70  and  71  will  show- one  of  the  means  of  dis- 
tinguishing it  from  the  similar  stable-fly;  it  will  be  noticed  that  the 
lowest  or  most  posterior  of  the  three  long  veins  in  the  wing  of  the  house- 
fly bends  upward  or  cephalad  at  almost  a  right  angle  while  the  corre- 


FIG.   72. — Last  three  segments  of  the  leg  of  the  house-fly,  showing  claws,  pulvillse 
and  hairs.      (After  Doane,  Insects  and  Disease.) 

sponding  vein  in  the  stable-fly's  wing  has  only  a  wide  curve  toward 
its  distal  end. 

What  is  the  reason  for  the  present  crusade  against  the  house-fly? 
It  is  not  merely  because  it  is  such  a  filthy  little  animal,  as  will  be  pres- 
ently noted,  but  because  it  is  one  of  the  worst  carriers  of  pathogenic 
bacteria  that  we  have;  this  is  particularly  true  of  the  germ  of  typhoid 
fever,  but  it  is  thought  that  several  other  diseases  are  spread  in  the 
same  way,  such  as  tuberculosis,  cholera,  dysentery,  smallpox,  diph- 
theria, etc.  It  has  been  suggested  that  we  call  the  house-fly  the  typhoid 
fly  to  remind  people  of  its  dangerous  habits.  The  fly  is  an  ideal  in- 
strument for  carrying  bacteria,  which  it  does  in  two  ways;  it  may  eat 
them  with  its  food  and  then  deposit  them  on  our  food  or  dishes  in  its 
excrement  as  "fly  specks,"  or  it  may  carry  them  mechanically  entan- 


ARTHROPOD  A 


93 


gled  in  the  hairs  and  folds  of  its  proboscis,  wings  or  legs.  The  wings  of. 
a  fly  when  examined  under  moderate  powers  of  the  microscope  are  found 
to  be  covered  with  thousands  of  tiny,  stiff  hairs,  too  small  to  show  in 
the  figures  here  represented,  and  the  legs  are  covered  with  numerous 
larger  hairs  as  shown  in  Fig.  72.  In  the  dirt  (see  Fig.  71)  that  collects 
among  these  hairs  is  room  for  millions  of  bacteria,  so  that  in  a  series  of 


FIG.   73. — Eggs  of  the  house-fly.      X  i .      (From  Howard,  House  Flies,  after  Newstead.) 

experiments  it  was  found  that  on  an  average  a  single  fly  may  carry  about 
1,250,000  bacteria;  these  bacteria  may  be  harmless  but  they  are  often 
the  germs  of  deadly  diseases.  Let  such  a  fly  crawl  across  a  culture  dish 
and  an  astonishing  trail  of  bacteria  will  develop  along  its  course. 
Where  these  bacteria  are  collected  is  easily  understood  when  the  breeding 


94  ECONOMIC   ZOOLOGY 

habits  of  the  house-fly  are  studied.  Nearly  anyone  knows  that  the 
unpleasant  maggots  seen  in  decaying  flesh  are  the  larvae  of  flies,  hatched 
from  the  eggs  laid  in  this  flesh  by  the  adult  females  in  order  that  these 
larvae  may  have  food  to  eat  while  they  are  developing  into  the  pupa  or 
chrysalis  stage.  These  maggots  may  or  may  not  be  the  larvae  of  house- 
flies,  probably  they  are  mostly  those  of  other  species;  but  anyone  may 
see  the  whole  process  by  watching  a  piece  of  stale  meat  some  summer's 
day.  Usually  one  will  not  have  to  wait  very  long  until  a  fly  will  light 
upon  the  meat  and  will  proceed  to  deposit  her  elongated,  white  eggs, 
possibly  at  the  rate  of  four  or  five  per  minute  until  a  hundred  or  more 
have  been  laid,  Fig.  73.  If  the  meat  be  kept  moist  and  warm  the  next 
day  will  probably  see  it  swarming  with  tiny  white  maggots;  these  larvae, 
in  a  few  days,  will  grow  to  full  size,  will  surround  themselves  with  little 
cases  and  become  pupae.  If  the  meat  be  in  a  covered  vessel  the  flies 
that  emerge  in  a  week  or  more,  from  these  chrysalises,  will  be  caught 
and  they  will  in  turn,  lay  a  new  lot  of  eggs,  though  it  may  be  a  couple  of 
weeks  after  hatching  before  the  flies  become  sexually  mature  and  are 
able  to  lay  eggs.  Since  each  fly  may  lay  one  hundred  or  more  eggs  in 
each  of  five  or  six  lots  per  year,  and  since  the  whole  life  cycle,  from  adult 
to  the  next  generation  of  adults,  may  take  place  in  three  or  four  weeks,  it 
will  be  seen  that  by  the  end  of  the  summer  the  descendents  of  the  first 
few  flies  are  to  be  numbered  by  millions;  hence  the  importance  of  "  swat- 
ting" the  first  flies  as  they  emerge  from  their  hibernation  quarters. 
The  life  history  of  the  house-fly  is  about  as  outlined  above,  except  that 
its  favorite  breeding  place  seems  to  be  in  damp  horse-manure,  though  it 
will  breed  in  almost  any  kind  of  filth  or  decaying  organic  matter;  for 
this  reason  the  name  " filth"  fly  has  been  suggested.  It  is  perfectly 
obvious  that  if  the  eggs  be  laid,  as  they  often  are,  in  human  excrement 
from  a  person  who  is  suffering  or  has  recently  suffered  from  typhoid 
fever  the  flies,  as  they  hatch  and  crawl  out  through  the  filth,  may  be  cov- 
ered with  typhoid  fever  germs  which  may  be  carried  to  another  person 
in  various  ways.  The  disgraceful  epidemics  of  typhoid  fever  that  raged 
in  our  army  camps  during  the  Spanish  American  war  were  probably 
largely  due  to  the  lack  of  care  in  protecting  the  soldiers  against  this 
kind  of  infection.  In  a  similar  way  flies,  by  feeding  on  the  sputum  (as 
they  often  do)  of  tuberculous  persons,  may  carry  the  germs  to  other 
persons.  Knowing,  now,  the  habits  of  the  house-fly  the  methods  of 
fighting  this  serious  pest  are  more  or  less  obvious;  they  consist  chiefly 


ARTHROPOD A 


95 


in  destroying  its  breeding  places,  and  secondarily  in  the  use  of  fly-traps, 
fly-paper,  etc.  In  towns  and  cities  this  is  comparatively  easy;  on  the 
farm  it  is  far  more  difficult.  The  screening  of  privies  and  cesspools, 
and  the  close  covering  of  garbage  cans  is  generally  not  difficult. 

It  is  the  handling  of  manure,  particularly  horse  manure,  that 
is  difficult.  In  cities  it  is  comparatively  easy  to  compel  owners  of 
private  and  livery  stables  to  keep  all  manure  in  closely  covered  bins 
so  that  flies  cannot  gain  access  to  it;  but  on  the  farm  this  is  far  more 


PIG.  74. — Maggot  trap  for  control  of  house-flies,  showing  the  concrete  basin 
of  water  in  which  the  larvae  are  drowned,  and  wooden  platform  on  which  the  manure 
is  piled.  (From  Howard,  House-Flies,  after  Hutchinson.) 

difficult.  If  not  practicable  to  keep  it  in  bins  the  manure  should  either 
be  spread  on  the  fields  every  day  or  two  where  it  will  dry  and  kill  the 
fly  eggs  and  larvae,  or  it  must  be  sprinkled  with  some  substance  that  will 
kill  the  flies  without  injuring  the  manure;  various  chemicals  have  been 
tried  for  this  purpose  with  the  conclusion  that  powdered  hellebore 
(using  3/2  lb.  to  10  gallons  of  water  for  each  8  bushels  of  manure)  is  the 
best  substance,  though  its  cost,  about  0.69  cents  per  bushel  of  manure, 
makes  it  fairly  expensive.  Perhaps  the  best,  and  in  the  end  the  cheap- 
est, solution  of  the  problem  is  to  build  a  " maggot  trap"  to  hold  the 


ECONOMIC   20OLOGY 


manure;  this  consists  of  a  wooden  platform  of  slats  over  a  shallow 
concrete  tank  of  water.  The  manure  is  piled  on  this  platform  and 
is  kept  wet;  the  maggots  in  their  migrations  fall  through  the  slats 
and  drown  in  the  water.  This  very  simple  arrangement,  Fig.  74,  is  said 
to  destroy  99  per  cent,  of  the  fly  larvae  in  the  manure.  Details  of 
construction  and  operation  may  be  obtained  from  the  U.  S.  Depart- 
ment of  Agriculture. 

The  trapping  and  poisoning  of  the  adult  fly  is  understood  by  most 
persons  and  a  vigorous  campaign  along  this  line  undoubtedly  helps 


A  R 

FIG.  75. — Termites.  A,  male  or  king  of  Termes  slightly  enlarged;  B,  female 
or  queen  of  Termes,  slightly  enlarged.  C,  worker  and  D,  soldier  of  Termes,  consider- 
ably enlarged.  (From  Hegner,  College  Zoology,  after  Cambridge  Natural  History, 
C  and  D  from  Grassi.) 

diminish  the  numbers  of  flies,  though  not  so  effectively  as  the  methods 
just  mentioned.  This  subject  is  also  treated  in  the  bulletins  issued  by 
the  Department  of  Agriculture. 

Termites  or  "white  ants,"  Fig.  75. — These  interesting  insects  are 
not  true  ants;  they  are  variously  classified  by  different  writers,  but  are 
usually  placed  in  the  order  Neuroptera.  There  are  a  hundred  or  more 
described  species  and  many  species  that  have  never  been  named. 
Their  colonial  mode  of  life  and  their  superficial  resemblance  to  ants 
have  doubtless  given  them  the  name  "white  ants."  As  among  the 
hymenopterous  colonies,  the  termites  exhibit  several  forms  of  indi- 


ARTHROPOD A 


97 


FIG.  76. — Work  of  western  white  ant,  Calotermes  sp.,  in  Mexican  walnut, 
Catalina  Mountains,  Arizona.  (From  Snyder,  White  Ants  as  Pests  in  the  United 
States  and  Methodsjof  Preventing  their  Damage.} 


98 


ECONOMIC   ZOOLOGY 


viduals,  Fig.  75,  the  workers,  soldiers,  kings  and  queens;  of  these  the 
workers  are  the  most  numerous  and  are  the  ones  that  do  the  damage. 
In  some  tropical  forms  the  queen  is  many  times  as  large  as  the  other 
forms.  In  warm  places  eggs  may  be  laid  at  any  time  during  the  year. 
At  times,  usually  spring  or  fall,  certain  winged  sexual  individuals  leave 
the  nest  in  large  numbers  and  swarm  in  new  places  to  start  new  colonies. 
These  "  flying"  ants  are  often  destroyed  in  enormous  numbers  by  birds. 
Termites  are  natural  wood  destroyers  and  live  in  colonies  of  usually 
several  thousand  individuals  in  decaying  logs,  dead  trees,  foundation 


PIG.  77. — Book  from  a  library  at  Van  Buren,  Ark.,  ruined  by  white  ants.  (From 
Snyder,  White  Ants  as  Pests  in  the  United  States  and  Methods  of  Preventing  their 
Damage.) 

timbers  of  houses,  fences  and  other  wood  in  contact  with  the  ground, 
and  in  complicated  underground  passages  usually  found  beneath  wood 
or  other  debris.  They  sometimes  work  from  these  colonies  up  into 
the  lower  floors  of  houses  where  they  riddle  the  floors  and  joists  with 
their  passages  until  nothing  but  a  shell  is  left  and  their  presence  is  first 
made  known  by  the  sudden  collapse  of  some  timber.  It  is  in  this  destruc- 
tion of  woodwork  that  the  white  ants  do  their  greatest  damage,  es- 
pecially to  timber  that  is  in  contact  with  moist  ground,  and  particularly 
in  tropical  and  sub-tropical  regions,  the  ravages  have  been  reported  as 


ARTHROPODA  g§ 

far  north  as  New  Hampshire  and  Michigan.  In  the  tropics  the  damage 
is  so  serious  that  in  some  places  all  important  buildings  are  being 
constructed  entirely  of  concrete.  In  hard  wood  their  main  passages 
usually  follow  the  course  of  the  grain,  as  shown  in  Fig.  76. 

Besides  the  damage  done  to  wood,  just  noted,  many  other  products 
are  injured;  for  example:  books,  Fig.  77;  clothing,  food,  etc.,  espe- 
cially if  stored  in  damp,  dark,  poorly  ventilated  cellars;  shrubs,  flowers 
and  nursery  stock;  and  field  crops  of  various  kinds. 

As  in  most  cases,  "an  ounce  of  prevention  is  worth  a  pound  of 
cure,"  and  it  is  better  to  protect  property  against  inroads  of  white 
ants  than  to  drive  them  out  after  they  have  come.  T.  E.  Snyder, 
(106)  of  the  U.  S.  Department  of  Agriculture  gives  the  following  sum- 
marized recommendations,  both  for  the  "prevention"  and  for  the 
"cure:" 

"How  Buildings  Should  be  Constructed  so  as  to  be 'White  Ant  Proof.' 

"Where  possible,  make  the  foundation  of  buildings  entirely  of  stone, 
brick,  or  concrete,  including  stone  columns  or  pillars  in  the  basement  to  sup- 
port the  floor  above;  make  the  walls  and  flooring  in  the  basement  or  cellar 
also  of  concrete,  and  lay  concrete  floors  on  a  giavel  base.  Fill  in  and  round 
off  points  of  juncture  between  concrete  walls  and  flooring  so  that  these  will 
not  meet  at  right  angles. 

"Where  stone  or  concrete  foundations  are  impracticable,  use  timber  im- 
pregnated with  coal-tar  cieosote. 

"Never  completely  surround  beams  with  mortar  or  brick;  leave  an  air 
space  around  the  beams  to  permit  air  circulation.  Set  beams  on  stone  or 
on  concrete,  not  in  the  earth  or  in  moist  concrete.  Rest  the  supports  of 
porches  or  steps  on  stone  or  concrete. 

"Lay  basement  window  sills  and  frames  over  concrete  and  do  not  allow 
the  woodwork  to  come  in  contact  with  the  ground.  Never  sink  untreated 
timber  in  the  ground  or  in  moist  concrete;  let  there  be  no  wood  in  contact 
with  the  ground  through  which  the  termites  may  come  up  from  subterranean 
galleries. 

"Complete  dryness  of  the  foundation  and  basement  walls  and  flooring 
is  an  important  means  of  rendering  buildings  safe  from  attack;  therefore, 
provide  for  air  spaces  between  the  ground  and  wooden  flooring  and  lay 
concrete  floors  on  a  gravel  base. 

"In  greenhouses,  replace  woodwork,  wherever  possible,  with  iron  frames 
and  concrete  work.  Treat  necessary  woodwork,  before  use,  with  a  i  per- 
cent, solution  of  bichlorid  of  mercury. 

"How  to  Eliminate  White  Ants  Already  Established  in  Buildings. 


100  ECONOMIC   ZOOLOGY 

"  Promptly  examine  the  foundation  timbers  and  other  woodwork  in  the 
basement  to  determine  the  approximate  point  of  entrance  and  the  extent  of 
damage  already  accomplished.  After  removing  the  damaged  wood,  drench 
the  ground  with  kerosene  oil. 

"Break  up  the  earthlike  shelter  tubes  by  means  of  which  white  ants  are 
sometimes  able  to  pass  over  the  surface  of  impenetrable  substances  in  order 
to  reach  woodwork,  and  drench  the  ground  beneath  with  kerosene  oil. 

"Then  replace  damaged  timber  with  rock,  brick,  or  concrete;  or,  if  this 
be  impracticable,  substitute,  for  the  foundation,  timbers  treated  with  coal- 
tar  creosote. 

"Since  termites  always  require  access  to  damp  earth,  shut  off  this  source 
of  moisture,  and  the  insects  will  not  be  able  to  extend  the  galleries  farther  and 
will  perish." 

Clothes  Moths. — It  is  probable  that  these  small  moths  have  been 
a  pest  ever  since  man  began  clothing  himself  in  skins  and  they  are 
particularly  mentioned  in  the  older  books  of  the  Bible.  They  are 
supposed  to  be  of  Old  World  origin  and  to  have  been  introduced  into 
America  in  early  Colonial  days.  They  are  common  everywhere;  in 
the  warmer  regions  being  destructive  at  all  times  while  further  north 
they  begin  their  depredations  with  the  advent  of  spring  or  early  summer. 
The  adults,  like  other  lepidoptera,  are  quite  harmless  as  they  take  no 
food  in  the  winged  state,  the  mouth-parts  being  rudimentary.  Though 
the  average  housekeeper  does  not  know  this,  it  is  perfectly  proper  to 
kill  the  tiny  flitting  moths  since  it  prevents  their  laying  eggs  that  will 
hatch  into  tiny  larvae  or  caterpillars,  which  are  the  destructive  agents. 
The  way  in  which  these  small  caterpillars  injure  woolen  goods,  furs, 
etc.,  is  only  too  familiar,  so  that  nothing  need  be  said  of  this. 

The  adults  lay  their  eggs  usually  upon  clothes  or  other  fabrics 
that  are  not  in  daily  use,  especially  if  these  materials  are  in  dark  places; 
and  if  not  disturbed  these  eggs  soon  hatch  into  the  larvae  that  ruin 
the  garments  upon  which  they  feed  and  from  which  they  construct 
their  tiny  bag-like  cocoons.  Fig.  78  is  the  common  species  in  the 
north;  there  are  also  the  southern  clothes  moth,  the  common  species 
from  Maryland,  south;  and  the  tapestry  moth,  the  rarest  of  the  three, 
a  more  brightly  colored  form  that  feeds  especially  upon  carpets, 
upholstering,  and  other  heavy  fabrics.  The  most  important^ thing  to 
know  about  all  of  these  species  is  how  to  prevent  their  damage;  this^is 
a  very  simple  matter  if  we  remember  that  the  adults  cannot  and  the 
larvae  will  not,  eat  paper . 


ARTHROPOD  A;    '.;•".',  ^ 


101 


Every  housekeeper  knows  that  cloths, ,  and ;  other ;  ;wojol$ijL  goods 
that  are  in  daily  use  are  seldom  if  ever  dairiaged  and  that  frequent 
vigorous  shaking  and  brushing  of  clothes  not  in  use  prevents  their 
being  eaten  by  moths;  this  means  simply  that  the  eggs,  if  they  have 
been  deposited  on  the  clothes  by  the  winged  adults,  are  brushed  off 
and  destroyed  before  they  have  time  to  hatch  into  the  feeding 
caterpillars. 

The  common  method  of  putting  away  winter  clothes  in  boxes 
or  closets  with  moth-balls  or  other  strong-smelling  substances  will 
be  effective  only  if  all  eggs  or  larvae  have  been  removed  from  the 
clothes  by  vigorous  brushing  and  shaking  before  putting  into  the  box 


FIG.   78. — The  case-making  clothes  moth,  Tinea  pellionella;  adult,  larva,  and  larva  in 
case.     (From  Marlatt,  The  True  Clothes  Moth,  after  Riley.) 


The  strong  odor  will  probably  keep  the  adults  from  coming  through 
the  cracks  into  the  box  to  lay  their  eggs,  but  if  the  eggs  are  already 
there,  they  will  probably  hatch  into  the  destructive  larvae  which  will 
not  be  affected  by  the  smell. 

As  the  smell  of  naphthalene  and  other  repellants  is  of  ten  disagreeably 
persistent  in  clothes  that  have  been  so  protected,  it  is  well  to  know 
that  it  is  entirely  unnecessary  to  use  these  substances  if  the  clothes 
be  tightly  wrapped  in  stout  paper,  after  being  thoroughly  brushed. 
For  years  the  writer  has,  each  spring,  packed  his  winter  clothes  in  the 
pasteboard  boxes  used  by  tailors,  and  then  tightly  wrapped  each  box 
in  several  thicknesses  of  newspapers,  creasing  all  corners  to  prevent 
the  possible  entry  of  the  slender  little  moths.  In  no  single  case  has 
any  damage  been  found  on  opening  these  boxes  in  the  fall.  The 


102  ECONOMIC  ZOOLOGY 

same  results  may'  be  secured  by  gumming  strips  of  paper  over  the 
joints  of  the  boxes. 

Upholstering  of  furniture,  etc.,  that  cannot  be  protected  in  this 
way  while  not  in  use  during  the  summer  may  be  protected  by  spraying 
with  naphtha  or  benzine,  every  six  or  eight  weeks,  if  precautions  against 
danger  from  fire  be  taken  with  these  inflammable  liquids.  In  some 
of  the  regular  storage  warehouses,  where  such  goods  may  be  sent, 
cold  storage  is  now  used  to  protect  goods  against  moths;  sometimes 
in  such  warehouses  periodic  fumigation  with  sulphur  dioxide  or  other 
gases  is  also  practised,  which  has  the  additional  effect  of  killing  all 
rodent  and  other  pests  that  may  be  present.  In  modern  houses  with 
well-fitted  fly-screens  clothes  moths  are,  of  course,  to  a  large  extent, 
excluded. 

Other  Household  Pests. — Roaches  usually  accompany  filth,  though 
they  sometimes  are  found  in  cracks  under  wash  boards,  in  cupboards 
and  in  other  places  where  food  stuffs  are  kept.  They  may  usually 
be  exterminated  by  a  vigorous  cleaning  of  cracks  and  corners  and  the 
use  of  borax  or  some  regular  roach  powder  that  is  sprinkled  about  in 
the  places  where  they  are  seen;  powdered  sodium  fluoride  is  said  to 
be  effective  if  used  in  this  way. 

Bedbugs,  the  horror  of  the  good  housekeeper,  are  sometimes  a  pest 
in  the  most  carefully  kept  house  in  the  city,  since  they  apparently 
come  through  cracks  in  the  walls  from  adjoining  houses  which  may  not 
be  so  carefully  looked  after.  The  use  of  modern  iron  bedsteads  elimi- 
nates largely  the  harboring  places  for  this  disgusting  pest,  and  in  old 
fashioned  wooden  beds  they  may  be  killed  by  spraying  the  cracks  with 
benzine,  or  similar  fluids,  care  being  taken  to  avoid  all  lights  while 
using  these  liquids.  In  cases  of  bad  infestations  with  these  or  other 
household  insects,  fumigation  with  hydrocyanic  acid  gas  is  most  effect- 
ive, but  owing  to  the  extreme  deadliness  of  this  gas  it  should  only 
be  used  according  to  rigid  directions  such  as  are  furnished  by  the  U.  S. 
Department  of  Agriculture. 

Fleas  occasionally,  for  some  reason,  multiply  very  rapidly  and  in- 
fest dwellings  beyond  the  point  of  endurance.  In  single  rooms  they 
may  sometimes  be  exterminated  by.  filling  the  air  and  covering  the 
floors  with  pyrethrum  insect  powder  and  closing  the  rooms  for  some 
hours;  the  powder  may  then  be  swept  up  and  burnt.  In  cellars  and 


ARTHROPODA  103 

places  filled  with  goods,  fumigation  with  hydrocyanic  acid  or  sulphur 
dioxide  may  be  used. 

Red  ants  sometimes  become  so  extremely  numerous  as  to  be  exceed- 
ingly annoying.  In  tropical  countries  these  tiny  insects  are  often 
so  numerous  that  it  is  necessary  to  set  each  leg  of  the  dining  room  and 
kitchen'  tables  in  a  cup  or  small  pan  of  oil  or  water  to  keep  the  food 
from  being  covered  with  them.  In  going  from  Hong  Kong  to  Canton, 
China,  by  the  night  boat,  a  few  years  ago,  the  writer  without  thinking, 
put  a  package  of  sandwiches  on  the  shelf  in  a  small  closet  in  his  state- 
room. Early  the  next  morning,  six  or  seven  hours  later,  when  he  went 
to  get  his  sandwiches  they  were  an  almost  solid  mass  of  tiny  red  ants 
and  had  to  be  thrown  overboard.  In  houses  the  red  ants  may  be  fought 
in  the  same  way  as  the  roaches  and  fleas,  but,  owing  to  their  small  size 
and  large  numbers,  their  extermination  is  often  a  matter  of  considerable 
difficulty. 

While  a  large  majority  of  the  insects  are  injurious  to  man,  as  has 
been  said,  there  are  numerous  forms  that  are  of  direct  or  indirect 
benefit  to  him.  For  example :  there  are  numerous  insects  that  are  used 
as  food  by  the  natives  of  the  tropics.  The  best  known  of  these  are  the 
grasshoppers  or  locusts.  "Locusts  and  wild  honey"  are  mentioned  in 
the  Bible  as  food.  In  the  markets,  of  Manila,  for  example,  may  be 
seen  on  the  stalls  piles  of  grasshoppers  with  the  appendages  removed, 
ready  for  cooking.  They  are  cooked  in  various  ways  or  may  even  be 
eaten  raw;  though  the  raw  locusts  are  said  to  be  of  very  disagreeable 
taste.  The  cooked  ones  are  said  to  be  really  delicious.  Nearly  every 
sort  of  insect  is  used  as  food  by  various  savage  tribes  in  various  parts 
of  the  world,  especially  the  fat,  juicy  grubs  or  larvae  of  beetles,  and  lepi- 
doptera.  The  enormous  queen  termites,  noted  above,  are  also  eaten. 

Honey-bees. — A  more  universally  esteemed  insect  diet,  especially 
among  civilized  peoples,  is  honey,  which  has  been  an  article  of  food 
from  earliest  times,  the  Bible  speaking^of  various  lands  that  "flowed 
with  milk  and  honey."  It  was  probably  the  "wild"  honey  that  was 
first  used,  just  as  it  is  still  used  occasionally,  when  a  "bee-tree"  is 
discovered;  but  the  keeping  of  bees  in  hives  so  that  all  the  honey  made 
by  them  might  be  easily  gathered  is  an  ancient  custom,  probably  origi- 
nating in  Southern  Asia,  or  in  the  East  Mediterranean  region.  The 
United  States  is  now  the  greatest  producer  of  honey;  in  1900  there  were 
produced  61,000,000  pounds  of  honey,  besides  750,000  pounds  of  bees- 


104  ECONOMIC   ZOOLOGY 

wax.  Many  large  apiaries  are  to  be  seen  in  California,  often  on  a 
sunny  slope  on  the  edge  of  a  desert.  In  this  state  there  is  a  succession  of 
flowers  throughout  the  entire  year  whereas  in  colder  climates  there  is 
a  winter  season  during  which  no  honey  is  manufactured.  The  various 
flowers  visited  by  the  honey  bees,  of  which  bees  there  are  some  1500 
species,  often  give  a  characteristic  taste  to  the  honey,  as  happens  for 
example,  in  some  sections,  when  buckwheat  is  in  bloom  and  the  bees 
swarm  over  the  fields  of  white  blossoms.  It  is  said  that  honey  is  some- 
times made  poisonous  by  the  bees  visiting  the  flowers  of  Mountain 
Laurel. 

Honey  is  not  only  a  delicious  food,  but  is  a  highly  nutritive  one; 
it  is  also  used  in  medicine.  It  is  frequently  adulterated  with  as  much 
as  75  per  cent,  glucose,  which  process,  though  it  is  a  true  adulteration, 
does  not  injure  the  honey  as  food. 

Silk-worms. — The  manufacture  of  silk  originated  probably  in  China 
about  3400  B.  C.  and  is  hence  one  of  the  oldest  of  human  industries. 
The  raising  of  silk- worms  was  introduced  into  Europe  in  552  A.  D.  and 
into  Virginia  about  1600.  The  production  of  raw  silk  has  never  been 
profitable  in  America  because  of  the  competition  with  cheap  Italian 
and  Oriental  labor  for  picking  the  cocoons  and  reeling  the  silk. 

The  introduction  of  power  looms,  such  as  may  be  seen  at  Paterson, 
N.  J.,  a  great  silk  centre,  has  revolutionized  the  manufacture  of  silk 
goods,  but  in  Canton,  China,  and  doubtless  in  other  places  in  the 
Orient,  the  old-fashioned  hand  loom,  crude  and  terribly  slow,  may  still 
be  seen. 

China  and  Japan  are  great  producers  of  raw  silk  and  can  probably 
increase  their  supply  almost  indefinitely  to  keep  up  with  the  demand. 
Japan  exports  some  11,000,000  pounds  per  year,  60  per  cent,  of  which 
comes  to  the  United  States.  The  original  source  of  the  raw  silk  is, 
of  course,  the  "silk-worm,"  the  larvae  of  a  moth,  of  which  there  are 
15  to  20  species;  the  best  known  of  these  silk-worms  is  Bombyx  mori, 
whose  habits  are,  briefly,  as  follows: 

The  female  lays  from  200  to  500  eggs,  which  hatch,  the  following 
spring,  into  tiny  caterpillars;  these  larvae  grow  very  rapidly,  feeding 
voraciously  on  mulberry  leaves,  until  they  are  about  3  inches  long, 
molting  several  times;  each  larva  then  spins  a  cocoon  of  silk  threads 
from  2000  to  3000  feet  long,  taking  about  five  days  for  the  process. 
The  spinneretts  are  in  the  mouth  and  the  silk-secreting  glands  (like 


ARTHROPODA 


105 


the  web-secreting  glands  of  spiders)  extend  nearly  the  entire  length 
of  the  body.  The  animal  swings  its  head  from  side  to  side,  hour 
after  hour,  carrying  a  tiny  thread  of  silk  across  with  each  vibration 
of  the  head.  From  this  cocoon  the  adult  moth  hatches  in  15  to  20 
days,  lays  her  eggs  and  dies.  The  cocoons  that  are  used  for  silk  are 
heated  to  kill  the  inclosed  larvae,  for  if  allowed  to  hatch  they  would  cut 


FIG.  79. — Caterpillar  with  cocoons  of  the  pupse  of  ichneumon  fly  parasites 
and  (above)  one  of  the  adult  ichneumon  flies.  The  lines  indicate  natural  dimensions. 
(From  Jordan  and  Kellogg,  Animal  Life.) 

the  silk  threads  in  emerging.  Sufficient  numbers  of  cocoons  are  kept 
alive  and  allowed  to  hatch  for  breeding  purposes.  The  utmost  clean- 
liness and  proper  temperatures  are  necessary  for  the  best  results.  The 
white  mulberry  furnishes  the  best  food  for  the  larvae,  though  the  black 
mulberry,  osage  orange  and  other  trees  may  be  used. 


106  ECONOMIC  ZOOLOGY 

Probably  all  the  conditions  for  the  production  of  raw  silk  could 
be  as  well  met  in  this  country  as  anywhere  else  except  that  of  handling 
the  cocoons;  so  long,  as  this  must  be  done  by  hand,  it  is  not  likely  that 
the  industry  here  can  successfully  compete  with  the  cheap  Oriental 
labor,  as  noted  above. 

Among  the  beneficial  insects,  perhaps  the  most  important  are 
those  that  help  us  control  the  destructive  ones.  These  may  be  divided 
into  the  predacious  forms  that  attack  and  devour  other  insects,  and 
the  parasitic  forms  that  spend  a  part  of  or  all  their  lives  on  or  in  the 
bodies  of  other  insects.  Among  the  predacious  forms  the  ladybird- 
beetles  are  perhaps  the  most  important.  These  little  beetles  destroy 
enormous  numbers  of  scale-insects,  plant-lice,  etc.  One  of  the  best 
examples  of  their  work  is  seen  in  the  work  of  the  Australian  ladybird- 
beetle,  Nowus  cardinalis,  that  was  introduced,  some  years  ago,  into 
California  to  control  the  cottony-cushion  scale  that  threatened  to  de- 
stroy the  citrus  fruit  industry  in  that  State.  The  beetles  soon  had  the 
scale  under  control  and  it  is  now  no  longer  considered  a  serious  pest. 
Other  species  of  ladybird-beetles  have  been  successfully  introduced 
into  the  United  States  and  many  of  our  native  species  are  destructive 
to  certain  species  of  aphis  and  scale-insects. 

Among  the  parasitic  insects  are  many  that  like  the  ichneumon 
flies,  lay  their  eggs  upon  or  in  the  bodies  of  caterpillars;  when  the 
eggs  hatch  the  larvae  feed  upon  and  eventually  kill  the  caterpillar, 
but  not  until  the  parasites  have  reached  the  pupa  stage,  ready  to  trans- 
form into  the  adult  insects  which  repeat  the  process,  Fig.  79.  But  for 
the  work  of  these  predacious  and  parasitic  insects  the  control  of  the 
destructive  forms  would  be  a  much  more  serious  problem  than  it 
already  is. 

The  value  of  dragon  flies  in  the  destruction  of  mosquitoes  has 
alreadv  been  mentioned. 


CHAPTER  X 
PISCES 

The  animals  discussed  in  this  and  the  following  chapters  all  belong  to 
the  phylum  Chordata.  This  rather  diverse  group  contains  animals 
that,  at  first  glance,  seem  to  be  very  slightly  related;  but  it  will  be 
found  that  they  all  possess,  in  a  more  or  less  typical  condition,  at  some 
period  in  their  life-history,  three  structures  or  groups  of  structures  that 
are  characteristic  of  the  phylum. 

The  first  of  these  is  the  notochord,  a  longitudinal,  dorsally  placed, 
cylindrical,  skeletal  axis,  Fig.  80,  nc,  which,  in  the  lower  members  of 
the  groups,  persists  throughout  life,  while  in  the  higher  forms  it  is 
replaced,  in  the  adult,  by  a  cartilaginous  or  osseous  back-bone. 

The  second  chordate  character  is  the  possession,  either  in  the  em- 
bryonic state  or  throughout  life,  of  a  series  of  slit-like  openings  between 
the  pharynx  and  the  exterior;  these  are  the  gill  or  visceral  clefts,  Fig.  80, 
g.  On  the  visceral  bars,  the  tissue  between  the  clefts,  are  found  in 
some  forms,  particularly  the  fishs,  numerous  branching,  vascular 
structures,  the  gills,  by  which  the  animal  extracts  oxygen  from  the 
surrounding  water. 

The  third  chordate  character  is  a  dorsally  placed,  hollow,  nervcus 
system,  Fig.  80,  s.c. 

The  phylum  chordata  is  usually  divided  into  three  or  four  sub-phyla 
somewhat  as  follows:  i.  Enteropneusta,  a  few  worm-like  animals  of 
rather  doubtful  relationships.  2.  Tunicata,  sea-squirts  and  other 
jelly-like  animals  that  are  more  or  less  common  in  the  sea.  3.  Cephalo- 
chorda,  a  small  group  of  small,  fishlike  animals,  called  lancets,  Fig.  80, 
which  exhibit  in  a  very  typical  way  the  above-mentioned  three  chordate 
characters  and  are  hence  extensively  used  to  illustrate  a  typical  chor- 
date. 4.  Vertebrata,  a  large  and  important  group,  including  all  of  our 
common  domestic  animals  and  others  having  a  vertebral  column  or 
back-bone. 

Of  these  four  subphyla  only  the  last  has  any  appreciable  economic 
value  except  as  zoological  specimens  or  objects  for  study,  so  that  the 
first  three  need  not  be  considered  further. 

107 


ECONOMIC   ZOOLOGY 


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The  subphylum  vertebrata,  the 
most  important  of  all  the  animal 
groups,  is  variously  divided,  by 
different  authors,  into  classes.  The 
older  classification  was  into  five 
classes:  I.  Pisces;  II.  Amphibia; 
III.  Reptilia;  IV.  Aves;  and  V. 
Mammalia.  As  a  matter  of  con- 
venience this  classification  will  be 
followed  here,  though  it  is  now  usu- 
ally customary  to  substitute  for  the 
first  class  three — the  Cyclostomata, 
lampreys  and  hags;  Elasmobranchii, 
sharks,  rays,  etc.;  and  Pisces,  the 
bony  and  other  more  or  less  typical 
fishes. 

The  enormous  importance  of 
fishes  as  food  and  in  other  ways  will 
be  discussed  later;  a  few  of  the  ways 
in  which  the  class  is  injurious  to 
man  will  first  be  noted. 

Cyclostomes,  Fig.  Si.  This  low 
group  of  fishes,  characterized  by  the 
circular,  suctorial  mouth,  the  absence 
of  paired  fins,  the  persistent  noto- 
chord,  and  other  primitive  charac- 
ters, comprises  the  lampreys  (Petro- 
myzon)  and  hags  (Myxine;  Bdello- 
stoma)  most  of  which  are  marine 
and  vary  in  size  from  6  to  36  inches. 
In  olden  times  lampreys  (lamperns) 
were  used  as  food;  now  they  are 
seldom  if  ever  eaten  in  this  country 
and  their  chief  importance  is  the 
damage  they  do  to  valuable  food- 
fishes.  The  larger  lampreys  attach 
themselves  to  the  bodies  of  other 
fish  and,  by  the  rasping  action  of 


PISCES 


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110  ECONOMIC  ZOOLOGY 

the  horny  teeth  that  cover  the  tongue  and  buccal  cavity,  they  cut 
through  the  body  wall  and  suck  out  the  blood  and  soft  parts  until 
the  victim  dies;  then  they  seek  another  host.  Fish  are  sometimes 
found  with  one  or  more  of  these  holes  in  the  body  wall,  through  which 
a  loop  of  the  intestine  may  protrude.  In  Cayuga  Lake,  New  York, 
some  years  ago,  serious  damage  was  done  the  food-fishes  by  the  large 
lake  lampreys  that  were  abundant  there,  so  that  a  systematic  warfare 
was  carried  on  to  exterminate  the  pests. 

The  hags  are  parasitic  in  the  same  way  upon  marine  fishes,  except 
that  they  enter  the  body-cavity  of  the  host  through  the  hole  they  cut, 
and  emerge  again  upon  the  death  of  the  victim.  Considerable  damage 
is  thus  done  the  fishing  industry  in  some  regions. 

Elasmobranchs. — In  this  group  are  found  the  sharks  and  rays, 
which  include  the  largest  of  all  the  fishes.  Their  value  as  food  will 
be  noted  below;  their  negative  importance  will  here  be  briefly  described. 
In  this  connection  the  so-called  man-eating  sharks  will  at  once  come 
to  mind.  To  what  extent  these  monsters  are  dangerous  to  man  is 
difficult  to  determine.  There  were  fish  specialists,  a  few  years  ago, 
who  expressed  great  doubt  as  to  whether  man  was  ever  attacked  by  any 
species  of  sharks,  and  it  is  probable  that  the  majority  of  sharks  are 
quite  harmless,  so  far  as  attacking  man  is  concerned.  It  is  difficult  to 
believe,  however,  that  all  the  stories  that  are  told  in  the  tropics  about 
man-eating  sharks  are  fabrications,  and  it  will  be  remembered  that 
during  the  summer  of  1916  there  were  several  apparently  authentic 
cases  of  loss  of  human  life  by  sharks  along  the  Atlantic  coast  of  the 
United  States;  for  example;  the  Baltimore  Sun  of  July  7, 1916,  had  these 
headlines:  "Shark  Kills  Bather.  Bites  off  both  Legs  of  Bellboy  at 
Springlake,  N.  J. — Second  Case  in  a  Week. " 

While  sharks  of  various  species  are  common  in  the  North  Atlantic 
these  visits  from  the  man-eaters  were  very  unusual  and  zoologists  had 
various  theories  to  explain  the  strange  phenomenon. 

The  shark  that  is  usually  called  the  "man-eater"  is  the  Great 
White  Shark,  genus  Carcharodon;  this  monster,  according  to  Jordan, 
reaches  a  length  of  25  feet;  Giinther  says  it  is  sometimes  40  feet  long 
and  has  been  known  to  cut  the  body  of  a  man  in  two  at  one  bite.  It  is 
an  inhabitant  of  tropical  and  subtropical  seas,  where  it  is  much  feared 
in  some  regions,  by  the  water-loving  natives.  The  other  sharks,  though 
they  may  reach  a  large  size,  are  probably,  as  has  been  said,  quite  harm- 


PISCES  III 

less  to  man,  but  are  often  injurious  in  other  ways.  For  example,  the 
small,  dogfish  sharks,  Mustelus  and  Squalus,  Fig.  82,  are  in  many 
places  very  destructive  to  lobsters,  crabs  and  various  food-fishes,  and 
to  squid  that  are  used  for  bait;  they  also  seriously  damage  nets  and 
other  fishing  gear.  It  is  estimated  that  these  dogfish  cause  a  damage 
of  at  least  $400,000  a  year  to  the  fisheries  of  Massachusetts.  Other 
larger  sharks  though  less  common  are  often  very  destructive  in  the  same 
way,  as  are  the  larger  skates.  It  is  not  uncommon,  in  pulling  a  seine, 
to  enclose  a  6-  or  8-foot  shark  that,  in  dashing  to  liberty,  tears  a 
great  hole  in  the  net  that  not  only  allows  other  fish  to  escape,  but  may 
take  hours  to  repair.  On  one  small  sandy  beach,  of  a  few  hundred 


FIG.   82. — Dog-fish,  Squalus  acanthias. 

yards  length,  on  the  coast  of  California,  I  once  counted  eight  sharks 
of  an  average  length  of  about  5  feet  that  had  been  drawn  out  of  the 
sea  in  one  morning  by  a  group  of  fishermen  who  were  seining  there. 
On  the  same  beach  were  often  seen  a  considerable  number  of  large 
rays  that  had  been  caught  in  the  same  way,  and  each  of  them  had  prob- 
ably caused  some  damage  to  the  nets.  It  is  no  wonder  that  the  fish- 
ermen despise  these  elasmobranchs. 

There  are  certain  rays,  known  as  sting-rays  or  "stingarees,"  in 
which  the  tail  is  armed  with  one  or  more  spines,  barbed  on  the  sides  and 
sometimes,  in  large  species,  8  or  9  inches  long.  These  rays  are 
more  common  in  warmer  waters  and  are  much  dreaded  by  fishermen 
as  they  can,  with  a  sudden  swing  of  the  tail,  inflict  an  ugly  wound  that 
may  be  excruciatingly  painful,  or  even,  according  to  Giinther,  cause 
death.  The  poison  that  enters  the  wound  made  by  the  spine  may  be 
merely  in  the  mucus  of  the  body  or  it  may  be  secreted  by  a  definite 
gland  at  the  base  of  the  grooved  or  hollow  spine. 


112 


ECONOMIC   ZOOLOGY 


Another  formidable  group  of  rays  are  the  torpedoes  or  electric  rays, 
Fig.  83.  There  are  several  species  of  the  genus  Torpedo,  some  of  them 
2  or  3  feet  across;  one  of  these  large  animals  may,  by  a  single 
discharge,  disable  an  adult  man,  according  to  Giinther.  The  elec- 
tricity is  generated  in  a  pair  of  flat,  curiously  formed  organs,  lying  on 
either  side  of  the  head.  The  electric  organs  are  thoroughly  enervated 

and  are  under  the  voluntary 
control  of  the  ray.  There  are 
also  electric  eels  that  are  cap- 
able of  giving  a  powerful  shock. 
Let  us  now  notice  several 
ways  in  which  '  the  elasmo- 
branchs  are  of  positive  economic 
importance.  In  many  coun- 
tries, especially  of  the  orient, 
the  smaller  sharks  and  some 
of  the  skates  are  used  as  food, 
either  salted,  dried  or  fresh. 
Some  negro  tribes  are  said  to 
allow  the  flesh  to  decay  before 
eating  it.  In  America  a  sense- 
less prejudice  exists  against  eat- 
ing sharks,  but  dogfish  are  now 
being  canned  and  sold  under  a 
trade  name  and  are  a  very  agree- 
able addition  to  our  list  of  food- 
fishes.  In  the  markets  of  China 
small  sharks  are  exhibited  for 
sale  the  same  as  the  ordinary 
food-fishes. '  Until  the  demand 
for  this  new  food  is  much  greater  the  excess  of  dogfish  and  other 
small  sharks,  captured  by  fishermen,  can  be  used  in  making  fertilizer. 
Therejte  a  limited  demand  for  the  smaller  sharks  by  colleges  and  uni- 
versities for  dissection  purposes  by  classes  in  zoology. 

In  China  and  India  the  fins  of  sharks  and  rays  are  extensively  used 
for  the  production  of  gelatine  and  their  collection  is  quite  an  important 
industry. 

Some  of  the  larger  sharks  are  useful  sources  of  oil;  a  basking  shark 


FIG.  83. — The  torpedo  or  electric  ray, 
Torpedo  occidentalis.  X/4-  (From  Dean, 
Fishes,  Living  and  Fossil.) 


PISCES  113 

may  produce  over  a  ton  of  this  substance,  which  is  obtained  mainly 
from  the  liver.  This  huge  fish  may  attain  a  length  of  over  30  feet. 

The  skin  of  certain  sharks  and  skates,  armed  as  it  is  with  sharply 
pointed,  tooth-like  scales,  is  sometimes  used  as  a  polisher  of  wood  and 
other  materials  and  is  known  as  shagreen. 

Pisces. — Under  this  head  will  be  noted  some  of  the  more  impor- 
tant of  the  so-called  teleost  or  bony  fishes;  the  Dipnoans  or  lung-fish, 
which  also  belong  in  this  group,  tho  extremely  interesting  zoologically, 
are  not  of  sufficient  economic  importance  to  warrant  discussion  here. 

It  is,  of  course,  as  food  for  man  that  these  fish  are  chiefly  important 
though  there  are  some  other  ways  in  which  they  are  economically  im- 
portant. For  example:  the  swim-bladder  of  the  sturgeon  and  some 
other  fish  is  used  to  make  isinglass,  fish-glue,  mock  pearls,  etc.;  the  men- 
haden, a  coarse  kind  of  herring,  is  caught  in  seins  by  the  ton  and  made 
into  oil  and  fertilizer,  several  dozen  fishing  steamers  being  engaged 
along  our  coasts  in  catching  them  and  conveying  them  to  factories 
on  shore;  cod-liver  oil  is  made  from  the  livers  of  various  species  of  cod- 
fish. 

The  importance  of  fish  as  a  food  product  is  best  appreciated  by 
visiting  a  large  fishery  along  the  North  Atlantic  coast  or  on  one  of  the 
great  rivers  of  either  coast.  Along  both  coasts  of  the  North  American 
continents  and  in  the  Great  Lakes  there  are  thousands  of  small  vessels 
constantly  engaged  in  the  catching  of  fish.  On  the  Columbia  River 
are  the  hugh  salmon  canneries  and  on  the  rivers  of  the  east,  are  the 
fisheries  for  herring,  shad,  etc.  Tens,  possibly  hundreds,  of  millions 
of  dollars  a  year  result  from  the  fisheries  of  the  United  States. 

While  most  species  of  fish  are  suitable  for  food  there  are  some  that 
are  poisonous  either  at  all  times  or  at  certain  seasons  of  the  year. 
L.  L.  Mowbray  (116)  says:  "Much  has  been  said  and  written  about 
the  poisonous  fishes  of  tropical  and  sub-tropical  seas.  It  is  a  known 
fact  that  among  people  eating  the  same  species  and  at  the  same  time, 
even  caught  in  the  same  locality,  some  have  been  poisoned,  while  others 
have  not.  Among  fishes  eaten  by  man,  the  species  considered  most 
likely  to  be  dangerous  as  food  during  the  season  from  May  to  October, 
are  the  barracuda,  two  species  of  kingfish,  three  species  of  jack,  red 
rockfish  and  tiger  rockfish."  .  .  .  "  All  these  fishes  are  carnivorous, 
preying  upon  various  species  of  fishes  and  invertebrates.  There  is  no 
evidence  whatever  that  they  feed  at  any  season  upon  forms  which  would 


114  ECONOMIC   ZOOLOGY 

render  their  flesh  unwholesome."  According  to  Dr.  Geogaghan  (116) 
once  medical  officer  of  the  Turk  Islands  there  are  two  forms  of  disease 
produced  by  these  fish:  one,  like  ordinary  ptomaine  poisoning,  coming 
on  10  to  20  hours  after  eating  the  fish,  acute  but  yielding  quickly  to 
treatment;  the  other  producing  slow  dull  pains,  especially  of  the  joints, 
coming  on  from  2  to  6  days  after  eating  the  fish  and  lasting  many 
months.  The  same  fish  that  cause  these  diseases  in  the  Turk  Islands 
and  Bahamas  are  eaten  at  Key  West  and  Bermuda  where  the  poisoning 
is  unknown.  The  reason  for  this  Mowbray  explains  as  follows: 

"After  observing  the  conditions  and  manner  in  which  the  fish  are  handled, 
I  have  reached  the  conclusion  that  the  reason  they  are  poisonous,  in  one  region 
and  not  in  another,  is  that  in  Bermuda  and  Key  West  almost  all  fishing 
boats  have  live-wells,  and  therefore  usually  bring  their  fish  to  market  alive, 
while  in  the  Turk  Islands  and  the  Bahamas  the  fish  are  killed  and  allowed 
to  remain  in  the  sun  until  the  shore  is  reached,  sometimes  5  or  6  hours 
after  they  are  caught.  All  of  the  fishes  considered  poisonous  are  of  soft 
flesh  and  rich  in  gastric  juices,  and  are  therefore  the  most  likely  to  decay 
quickly;  and,  when  eaten  in  a  partially  decayed  condition,  cause  ptomaine 
poisoning.  Naturally,  some  are  more  poisonous  than  others.  Those  caught 
in  the  morning  are  exposed  to  the  sun  rays  much  longer,  and  are  therefore 
much  more  decomposed." 

It  would  seem  from  this  that  possibly  the  poisonous  character  of 
fishes  is  largely  a  matter  of  their  being  more  or  less  decomposed,  though 
it  is  thought  by  some  to  be  due  to  the  character  of  the  food  eaten  at 
different  seasons. 

The  most^  important  of  the  world's  food-fishes  are  said  by  some  to 
be  the  herrings.  This  family  (Clupeidae)  includes  considerably  over 
100  species  and  is  probably  more  numerous  in  individuals  than  any 
other  family  of  fishes. 

The  common  herring  (Clupea  harengus]  is  one  of  the  most  important 
of  all  food  fishes;  it  is  caught  in  nets  in  enormous  numbers  along  the 
Atlantic  coasts  of  both  North  America  and  Europe.  For  example  at 
Port  Deposit,  Maryland,  a  fishing  station  on  the  Susquehanna  River, 
these  fish  are  caught  in  huge  seines,  hundreds  of  feet  long,  which  are 
hauled  in  by  an  engine  or  by  horse-power  upon  a  floating  dock;  100,000 
fish  may  be  brought  in  at  one  time  in  this  way.  They  are  cleaned, 
salted  and  packed  in  barrels  on  the  spot  so  that  they  have  no  oppor- 
tunity to  decay  in  the  least.  It  has  been  estimated  that  at  least 
10,000,000,000  herring  are  caught  annually  by  British  and  American 


PISCES  115 

fishermen.  There  has  been  much  uncertainty  as  to  the  habits  of  the 
true  or  sea-herring.  It  is  supposed  that  there  are  numerous  races, 
each  of  which  swims  in  a  separate  school,  sometimes  in  such  enormous 
numbers  that  they  form  a  closely  crowded  mass  of  from  5  to  20  square 
miles.  These  schools  migrate  from  the  deep  sea  toward  the  coasts 
where  they  spawn.  •  The  river-herrings  or  alewives  are  the  ones  that 
were  mentioned  above  as  being  caught  in  large  numbers  as  they  ascend 
the  rivers  of  the  Atlantic  coast  to  spawn,  they  are  largely  smoked  and 
salted. 

The  shad,  one  of  the  finest  of  all  food  fishes,  belongs  to  the  herring 
family,  and,  like  it,  is  caught  in  the  rivers  of  the  Atlantic  seaboard, 
which  it  ascends  for  the  purpose  of  spawning.  Being  a  large,  finely 
flavored  fish  it  is  usually  eaten  fresh,  while  the  common  herring  is  largely 
salted  or  smoked.  The  shad  was  successfully  introduced  into  Cali- 
fornia, years  ago,  and  is  now  abundant  from  Monterey  Bay  to  Alaska. 

In  spite  of  the  fact  that  it  is  very  prolific,  an  average  female  pro- 
ducing from  30,000  to  100,000  eggs,  while  many  individuals  produce 
several  times  that  many,  the  shad  has  been  largely  reduced  in  numbers, 
with  a  corresponding  rise  in  price.  But  for  the  work  of  the  United 
States  Bureau  of  Fisheries,  to  be  discussed  later,  this  delicious  fish 
would  probably  have  been  practically  exterminated.  In  1900  this 
Bureau  hatched  and  distributed  241,056,000  shad  fry. 

Although,  as  noted  above,  shad  produce  eggs  in  enormous  numbers, 
they  are  deposited  more  or  less  at  random  in  the  fresh  water  of  the 
rivers,  no  nest  is  built  and  the  percentage  of  loss  of  eggs  is  very  high; 
added  to  this  is  the  destruction  by  other  fish  and  by  man  (who  always 
catches  them  on  the  way  to  the  breeding  grounds),  so  that  it  is  no 
wonder  the  industry  was  threatened  with  extinction. 

After  spawning,  the  adults  begin  to  feed  again,  and  move  toward 
the  sea.  The  young  shad  remain  in  the  rivers  until  about  November 
of  the  first  season  when  they  are  about  3  inches  long;  they  remain  in 
the  sea  for  3  or  4  years,  till  sexually  mature,  when  the  female  may 
weigh  from  3  to  6  pounds  or  more.  The  shoreward  migration  of 
shad  depends  upon  the  temperature  of  the  water;  it  begins  along  the 
southern  coasts  and  gradually  extends  northward  as  far  as  the  St. 
Lawrence  River. 

Another  important  member  of  the  herring  family  is  the  sardine, 
the  tiny  fish  characteristic  of  the  Mediterranean  Sea  and  presumably 


Il6  ECONOMIC   ZOOLOGY 

named  from  the  Island  of  Sardinia.  The  sardine  is  the  most  important 
fish  of  France.  There  are  about  100  canneries  for  sardines,  some  of 
which  have  an  annual  output  of  5,000,000  cans.  There  are  various 
small  species  of  the  family  Clupeidae  that  are  known  as  sardines,  the 
typical  French  species  being  the  young  pilchard,  C.  pilchardus. 

On  the  coast  of  California  is  a  small  fish,  somewhat  larger  than  the 
French  sardine,  that  is  canned  in  the  same  way  in  which  the  Mediter- 
ranean species  is  preserved,  it  is  a  true  sardine,  C.  cacruteus.  Eastport, 
Me.,  is  the  chief  centre  for  sardines  in  the  United  States.  The  annual 
output  of  the  canneries  of  Maine  is  about  550,000  cases,  valued  at  about 
$2,000,000. 

The  cod-fish  (Gadus  morrhua)  is  one  of  the  most  important  of  all  the 
food  fishes;  it  reaches  a  length  of  3  or  4  feet  and  is  characteristic  of 
colder  seas.  As  long  ago  as  1415  English  fishermen  sought  the  cod-fish 
on  the  coast  of  Iceland  and  since  the  sixteenth  century  they  have  been 
coming  to  the  banks  of  Newfoundland.  It  is  said  that  more  than  half 
the  human  population  of  Newfoundland  get  a  living  through  the  cod 
fisheries.  It  is  also  an  important  business  in  the  North  Atlantic 
region  of  the  United  States.  Unlike  the  preceding  the  cod  is  caught 
with  set-lines  and  hand-lines,  rather  than  with  seines,  tho  trap-nets  are 
also  used  When  brought  to  shore  the  fish  are  largely  split  open, 
rubbed  with  common  salt,  and  then  thoroughly  dried  by  spreading  them 
on  platforms  of  boughs,  known  as  "  flakes,' '  in  the  sun.  In  good  weather 
the  fish  will  be  cured  in  a  week  and  is  then  hard  and  stiff.  Each 
fish  is  turned  over  at  least  once  a  day  so  that  both  sides  may  be  cured. 

The  cod  spawns  at  moderate  depths  and  the  eggs  rise  to  the  surface 
of  the  sea,  where  they  remain  till  hatched.  An  average  sized  cod  is 
said  to  produce  from  2,000,000  to  4,000,000  eggs  a  year. 

The  haddock  is  another  well-known  food  fish  belonging  to  the  cod- 
fish family. 

The  salmon  family  (Salmonidae)  includes  many  of  our  finest,  largest 
and  gamiest  food  fishes,  since  besides  the  salmon  proper,  whose  very 
name  (from  sa^io,  to  leap)  indicates  its  active  vigorous  nature,  the 
family  includes  various  species  of  trout  and  white  fish.  While  the 
trout  are  more  popularly  known  to  sportsmen  and  others,  the  great 
Quinnat  or  King  Salmon  of  the  Columbia  River  is  economically, 
the  most  important  member  of  the  family,  if  not  of  all  the  fishes  of  the 
country.  This  magnificent  fish,  sometimes  weighing  75  pounds,  is 


PISCES 

caught  as  it  enters  the  Columbia  and  other  rivers  of  the  Pacific  coast  by 
various  mechanical  contrivances;  it  is  caught  by  the  ton  and  is  largely 
canned,  on  the  spot.  In  1908  the  salmon  fisheries  were  estimated  at 
$10,500,000.  This  wholesale  destruction  of  these  animals  on  the  way 
to  their  breeding  grounds  would  doubtless  long  ago  have  seriously 
impaired  the  business  but  for  the  work  of  the  U.  S.  Bureau  of  Fisheries. 
The  remarkable  life  of  this  fish  is  too  well  known  to  need  more  than  a 
mention  here — how  it  leaves  the  sea  as  sexual  maturity  approaches, 
ascends  the  rivers,  often  for  hundreds  of  miles,  swimming  rapids, 
jumping  water-falls  and  overcoming  astonishing  obstacles  until  it 
reaches  the  quiet  protected  headwaters  where  the  eggs  may  be  deposited 
in  safety;  how  the  adults,  wasted  and  torn  by  their  long  foodless  journey, 
die  without  ever  regaining  their  native  ocean;  how  the  eggs  hatch  into 
the  tiny  fish  that  gradually  work  their  way  down-stream,  feeding  as  they 
go,  until  they  reach  the  ocean  as  vigorous  young  salmon,  able  to  dart 
about  and  escape  the  many  enemies  of  the  deep;  and  how  these  young 
salmon  remain  in  the  sea  until  they,  in  turn,  have  reached  sexual 
maturity,  when  some  mysterious  impulse  impels  them  to  leave  the 
ocean  and  ascend  the  rivers  to  certain  death,  that  their  kind  maybe 
perpetuated.  It  is  a  wonderful  illustration  of  the  way  nature  often 
sacrifices  the  individual  for  the  good  of  the  race. 

Swordfishes,  Fig.  84,  are  an  interesting,  though  not  a  very  important 
group.  They  are  the  largest  of  the  teleost  fishes  sometimes  reaching  a 
length  of  12  or  15  feet.  The  flat,  blade-like  snout  which  gives 
them  their  name  is  a  very  effective  weapon,  with  which  they  are  said 
to  attack  and  kill  whales;  and  it  has  been  frequently  reported  that  they 
have  punctured  the  bottoms  of  small  wooden  boats,  possibly  mistaking 
them  for  their  cetacean  enemies,  though  why  they  should  attack  a 
whale  at  all  is  not  clear.  Swordfish  "steaks"  are  a  common  article 
of  diet  in  New  England  and  elsewhere,  and  while  perhaps  not  so  delicate 
as  some  of  the  smaller  fish,  they  are  excellent  food.  A  common  method 
of  capture  of  these  large  fish,  which  can  cut  their  way  out  of  an  ordinary 
net,  is  to  harpoon  them  from  a  small  platform  fixed  on  the  bowsprit  of  a 
small  sailing  or  power  boat;  it  is  a  form  of  sport  requiring  both  patience 
and  great  skill. 

The  sturgeons,  Fig.  85,  are  the  largest  of  the  freshwater  fishes  of  the 
northern  hemisphere  where  they  occur.  They  may  reach  a  length  of 
10  feet  and  are  covered  with  hard,  bony  plates.  Their  flesh  is  used  as 


n8 


ECONOMIC   ZOOLOGY 


food  and  their  eggs,  which  are  small  and  produced  in  enormous  num- 
bers (one  female,  it  is  estimated,  may  produce  3,000,000  in  one  season) 
are  made,  especially  in  Russia,  into  Caviare.  Besides  this,  from  their 
air-bladder  is  made  isinglass,  as  was  noted  above. 

Besides  these  few,  hundreds  of  species  of  useful  fishes  might  be 
mentioned,  as  there  are  probably  but  few  that  are  not  used  as  food  by 
somebody,  somewhere. 


' 


FIG.  84. — Sword-fish  (Tetraptu'rus),  yellow-fin  tuna,  and  yellow  tail,  caught 
with  rod  and  reel  at  Santa  Catalina  Island.  (From  Dougherty,  Economic  Zoology, 
after  Bulletin  of  B.  of  F.,  vol.  xxviii,  1908.) 

Fish-culture. — The  possibilities  of  fish-culture  have  been  long  recog- 
nized. This  science  was  practised  in  early  ages  by  the  Chinese  and  later 
by  the  Romans.  It  was  introduced  into  the  United  States  about  1865; 
and  in  1871  the  federal  government  established  the  United  States  Fish 
Commission,  now  known  as  the  Bureau  of  Fisheries.  While  the  chief 
work  of  this  Bureau  is,  perhaps,  the  artificial  propagation  of  food 


PISCES 


119 


fishes,  it  also  looks  after  the  lobster,  shell-fish,  sponge  and  other 
industries  dealing  with  aquatic  life.  It  also  controls  laboratories  for 
research  at  Woods  Hole,  Mass.,  Beaufort,  N.  C.,  and  elsewhere.  It 


owns  several  vessels  equipped  for  deep-sea  dredging  and  other  lines  of 
marine  investigation;  also  several  railway  cars  fitted  with  tanks, 
aerating  pumps,  living  quarters  for  attendants,  etc. 


which  are  used  in 


120  ECONOMIC   ZOOLOGY 

transporting  young  fish  from  place  to  place.  In  1901  the  Bureau 
planted  somewhat  over  1,164,000,000  fish  in  waters  of  the  United 
States.  About  Y±  of  these  were  whitefish  and  J£  were  shad. 

Many  of  the  individual  States  have  their  own  fish  commissions 
with  numerous  hatcheries  conveniently  located.  In  Europe  there 
are,  or  were  before  the  war,  more  than  400  fish  hatcheries,  more 
than  half  of  which  were  operated  profitably  by  private  individuals;  it 
is  claimed  that  a  profit  of  1500  per  cent,  had  been  made  in  this  work. 

The  primary  object  of  fish-culture  is  to  increase  the  proportion  of 
eggs  that  hatch  and  to  protect  the  embryos  and  young  fish  until  they 
have  safely  passed  the  perils,  of  early  life  and  are  able  to  take  care  of 
themselves.  As  in  most  animals  the  young  fish  are  very  helpless  and, 
under  natural  conditions,  easily  fall  prey  to  various  enemies  or  are  de- 
stroyed by  unsuitable  environmental  conditions;  the  result  is  that  the 
struggle  for  existence  is  extremely  severe  and  the  mortality  enormous. 
Under  the  artificial  conditions  of  the  hatchery  natural  enemies  of  the 
young  fish  are  excluded,  and  the  environment  is  made  as  ideal  as  pos- 
sible without  making  it  too  unnatural.  In  nature  the  loss  begins  with 
fertilization.  Where  the  eggs  are  fertilized  in  the  open  water  of  a  pond 
or  swiftly  running  stream  it  is  obvious  that  many  may  easily  escape 
coming  in  contact  with  spermatozoa;  these  of  course  will  die  and  be 
lost.  This  loss  is  almost  entirely  avoided  in  the  hatchery  by  the  process 
of  " stripping"  and  artificially  mixing  the  eggs  and  sperm.  In  this 
process  the  male  and  female  fish  are  carefully  caught,  at  the  time  of 
sexual  maturity,  and  stripped  of  their  eggs  and  spermatozoa  (roe  and 
milt)  by  holding  over  a  vessel  and  gently  pressing  out  the  roe  or  milt. 
Both  fish  must  be  ripe  or  fertilization  will  not  take  place.  If  ripe  the 
belly  of  the  fish  feels  soft  and  flabby,  and  if  it  be  held  up  by  the  head  the 
eggs  will  settle  down  toward  the  vent  and  almost  run  out  without  out- 
side pressure.  If  not  ripe  the  belly  of  the  fish  feels  firm  and  consider- 
able pressure  must  be  exerted  to  strip  out  the  eggs. 

The  eggs  are  first  stripped  into  a  perfectly  clean  vessel  with  a  small 
amount  or  even  no  water;  then  the  milt  is  stripped  into  the  same 
vessels  and  the  mass  gently  shaken  to  insure  thorough  mixing  of  eggs 
and  sperm.  Fertilization  takes  place  at  once;  after  allowing  the  mass 
to  stand  for  15-20  minutes  it  is  rinsed  in  clean  water  and  transferred 
to  the  hatching  trays.  By  this  process  from  90  per  cent,  to  100  per 
cent,  of  the  eggs  will  be  fertilized  and  an  enormous  saving  over  the 
natural  method  will  result. 


PISCES  121 

While  in  the  hatching  trays  the  eggs  are  examined  frequently,  and 
are  sometimes  stirred  and  rolled  over  with  feathers;  sometimes  they  are 
stirred  by  raising  and  lowering  the  trays  in  the  water;  and  any  eggs  that 
escaped  fertilization,  or  for  any  other  reason  have  died,  are  carefully 
removed  before  they  have  time  to  mold  or  decay  and  infect  the  good 
eggs.  A  dead  egg  has  a  sort  of  opaque  appearance  that,  with  a  little 
experience,  is  easily  recognized.  The  hatching  trays  are  of  various 
types,  a  common  form  being  a  box  about  15  X  24  inches  and  6  inches 
deep  made  of  galvanized  wire  netting.  These  trays,  containing 
thousands  of  eggs,  are  usually  placed  in  narrow,  wooden  troughs  with  a 
series  of  transverse  partitions  so  arranged  that  the  stream  of  water  that 
passes  through  them  is  forced  upward  through  the  eggs  in  the  tray 
and  keeps  them  thoroughly  mixed  and  aerated.  The  arrangement  of 
trays,  etc.,  varies  at  different  hatcheries  and  with  varying  conditions. 

In  a  month  or  more,  varying  with  the  temperature  of  the  water  and 
other  conditions  the  eggs  hatch  and  the  young  fish,  with  the  huge  yolk 
sack  attached,  wriggle  out  of  the  trays  and  are  taken  care  of  until  the 
yolk  is  absorbed  and  the  fish  are  active  and  able  to  take  care  of  them- 
selves if  liberated  into  the  waters  of  a  suitable  stream.  While  the  yolk  is 
still  present  the  fish  will  not  feed,  but  if  they  are  kept  longer  they  must 
be  fed  at  frequent  intervals  on  finely  minced  liver  or  other  meat,  great 
care  being  taken  to  prevent  fouling  of  the  water  by  uneaten  scraps  of 
meat. 

One  of  the  primary  factors  in  handling  the  eggs  and  young  fish  is 
cleanliness.  Unless  the  water  is  of  exceptional  purity  it  must  be  led 
into  settling  tanks  where  the  heavier  sediment  settles  to  the  bottom 
and  then  it  may  be  necessary  to  strain  it  through  cloth  to  remove  the 
finest  particles  of  foreign  matter  that  in  the  open  streams,  settles  over 
the  eggs  and  causes  high  mortality.  Another  factor  is  a  free  circulation 
of  water  in  sufficient  quantity  to  keep  the  eggs  in  motion  and  to  keep 
them  well  aerated.  It  is  often  important  that  the  temperature  of  the 
water  be  low  during  the  season  when  hatching  is  in  progress. 

When  the  young  fish  or  "fry"  have  reached  a  proper  size  it  is  often 
necessary  to  transport  them  long  distances  to  the  place  where  they  are  to 
be  liberated.  For  this  purpose,  as  noted  above,  the  Bureau  of  Fisheries 
employs  several  cars  with  tanks  and  aerating  devices.  The  vessels 
most  commonly  used  for  handling  the  fry  are  the  ordinary,  large 
milk  cans,  holding  about  15  gallons.  The  water  in  these  cans  must 


122  ECONOMIC   ZOOLOGY 

be  kept  cool,  which  in  summer  may  necessitate  the  use  of  ice,  and  it 
must  be  either  aerated  or  frequently  changed.  It  is  sometimes  possible 
to  keep  it  sufficiently  aerated  by  dipping  it  out  with  a  cup  and  pouring 
it  back  from  some  height. 

In  some  cases  it  is  desired  to  ship  the  eggs  to  a  distant  point,  where 
their  further  development  will  take  place.  This  is  done  in  various  ways. 
In  some  instances,  light  wooden  boxes  are  used  and  the  eggs  are  packed 
as  follows:  a  layer  of  damp  material,  preferably  sphagnum  moss,  is 
placed  in  the  bottom;  over  this  a  sheet  of  wet  cheese  cloth  is  spread  upon 
which  a  layer  of  eggs  is  laid;  over  the  eggs  another  sheet  of  cloth  and 
another  layer  of  damp  moss  are  placed  and  this  is  repeated  until  a 
dozen  or  more  layers  are  present,  perhaps  with  a  horizontal  partition 
or  two  of  wood  to  prevent  too  great  pressure  on  the  bottom  eggs.  This 
box  is  now  packed  in  the  centre  of  a  larger  box  with  dry  moss  or  other 
shock-absorbing  material  and  may  be  sent  on  a  journey  of  several  days' 
duration.  In  warm  weather  various  methods  are  used  to  keep  the  eggs 
cool. 

The  above  is  a  brief  account  of  the  general  methods  of  fish  culture; 
the  method  varies  with  the  different  species  of  fish,  with  the  locality, 
and  with  other  varying  conditions. 

There  are  many  farms,  remote  from  the  coasts  or  from  large  bodies 
of  water,  where  fresh  fish  are  almost  an  impossible  luxury.  In  many 
cases  there  are,  or  could  be  constructed,  on  these  farms,  large  ponds, 
often  used  for  the  gathering  of  ice,  where  fish  in  sufficient  numbers  to 
supply  the  family  could  be  raised  at  a  nominal  cost.  If  the  pond  be 
surrounded  by  a  rank  growth  of  vegetation  it  will  support  a  considerable 
number  of  fish;  if  the  pond  be  new  or  have  a  more  artificial  environment 
the  fish  will  probably  have  to  be  fed.  The  kind  of  fish  best  suited  to 
the  pond  will  have  to  be  determined  by  the  local  conditions.  For  ex- 
ample if  the  water  be  sluggish  carp  or  cat-fish  will  have  to  be  raised; 
if  there  be  a  fairly  rapid  circulation,  changing  the  entire  body  of  water 
every  week,  bass  or  perch  may  be  kept;  if  the  circulation  be  sufficient 
to  change  the  water  every  day  or  two  trout  may  be  raised.  The 
pond  may  be  stocked  with  a  few  adults  or  by  planting  eggs  or  fry, 
which  may  probably,  in  most  cases,  be  obtained  from  the  nearest  State 
hatchery  or  from  the  U.  S.  Bureau  of  Fisheries.  Various  bulletins 
upon  the  subject  have  been  published  that  give  specific  directions. 


CHAPTER  XI 
AMPHIBIA  (BATRACHIA) 

As  the  name  indicates  this  is  a  class  of  animals  that  have  two  modes 
of  life,  aquatic  and  terrestrial.  The  eggs  are  usually  laid  in  water  and 
hatch  into  fish-like  tadpoles  that  may  later  give  up  their  aquatic  habits 
and  live  on  land.  Nearly  all  of  them  breathe  by  gills,  in  the  larval 
condition,  and  many  of  them  retain  these  gills  through  life,  though  lungs 
are  usually  present  in  the  adult,  sometimes  being  present  in  the  same 
animal  with  the  gills.  The  Amphibia,  though  so  fish-like  in  many  cases, 
are  distinguished  from  the  Pisces,  by  having  pentadactyle  limbs,  usually 
without  claws,  in  place  of  paired  fins  (where  paired  appendages  are 
present  at  all)  and  by  the  absence  of  fin-rays  in  the  median  fins,  where 
these  organs  are  present.  The  skin  is  glandular  and  a  bony  dermal 
exoskeleton  is  sometimes  present.  There  are  also  numerous  character- 
istics of  internal  structures  that  need  not  be  noted  here. 

The  Amphibia  are  interesting  as  illustrating  the  transition  from 
water-breathing  to  air-breathing  forms.  The  lower  species  retain  their 
gills  throughout  life,  while  the  higher  forms  lose  their  larval  gills  and 
breathe  entirely  by  means  of  their  lungs  and  skin.  This  metamor- 
phosis from  the  tadpole  to  the  adult  may  take  place  in  a  few  months  or 
it  may  take  a  much  longer  time.  Coincident  with  the  disappearance  of 
the  gills  and  the  development  of  the  lungs  the  limbs  usually  make  their 
appearance,  the  tail  is  absorbed,  and  other  marked  external  and  inter- 
nal changes  take  place,  Fig.  86. 

As  noted  later,  the  tailed  amphibia  are  very  commonly  confused 
with  certain  reptiles  and  called  lizards;  but  they  may  usually  at  once 
be  distinguished  from  the  latter  by  the  absence  of  scales  and  claws  and 
by  differences  of  habits,  the  former  being  usually  found  in  dark,  moist 
places  while  the  latter  prefer  dry,  sunny  localities. 

There  are  fewer  known  species  of  living  Amphibia  than  of  any  of  the 
vertebrate  classes,  the  estimates  varying  from  about  noo  to  2200. 
With  the,  extinct  forms  we  are  not  especially  concerned  since  they  can 

123 


124 


ECONOMIC   ZOOLOGY 


scarcely  be  said  to  have  any  economic  value,  except,  perhaps,  in  the 
determination  of  geological  horizons.  As  in  other  groups  the  classifica- 
tion of  the  Amphibia  varies  with  different  authors;  the  extinct  forms  are 
usually  placed  in  two  or  three  orders,  the  living  forms  in  the  following 
three  orders:  i.  Apoda  or  Gymnophiona  are  legless,  snake-like  or  worm- 
like  forms  found  chiefly  in  the  tropical  and  subtropical  countries;  2. 


FIG.  86. — Metamorphosis  of  the  frog.  Tadpoles  in  different  stages  of  develop- 
ment, from  those  just  hatched  (i)  till  the  adult  form  is  reached  (8).  1-3,  about 
life  size;  2a,  enlarged;  4-8,  somewhat  reduced.  (From  Hegner,  College  Zoology, 
after  Mivart.) 

Caudata  or  Urodela  are  the  tailed  Amphibia,  such  as  mud-puppies,  sala- 
manders, etc.;  3.  Salientia  or  Anura  are  the  tailless  forms,  the  frogs  and 
toads.  Of  these  three  orders  the  last  is  by  far  the  largest  and  the  first 
the  smallest.  In  cold  regions  the  amphibia  hibernate  through  the  se- 
vere winter  weather  by  burying  themselves  in  the  ground  or  in  the  mud 
and  leaves  at  the  bottom  of  ponds  and  streams.  Being  inoffensive 


AMPHIBIA  (BATRACHIA) 


125 


creatures  they  depend  for  protection  upon  their  activity,  their  protec- 
tive coloration  and  in  some  cases,  upon  poison  glands  in  the  skin. 
Many  of  them  have  considerable  power  of  regenerating  lost  parts. 


PIG.  87. — Mud  puppy  or  water  dog.     Necturus  maculatus.      X;H}. 


FIG.   88. — Hellbender  or  "Alligator, "  Cryptobranchus  allegheniensis. 

Although  not  one  of  the  more  important  groups  economically,  prac- 
tically all  of  the  Amphibia  are  of  some  value  to  man,  and  few  if  any  are 
more  injurious  than  beneficial. 


126  ECONOMIC   ZOOLOGY 

Of  the  Apoda  little  need  be  said;  although  they  feed  on  worms  and  in- 
sect larvae,  they  are  not  numerous  enough  to  be  of  great  importance. 

The  Caudata  which  are  represented  by  several  more  or  less  popularly 
known  species  are  probably  of  considerable  value  as  destroyers  of  in- 
sects. Even  the  smaller  salamanders,  Fig.  89,  that  are  more  numerous 
than  is  commonly  supposed  because  they  are  largely  nocturnal  and 
secretive  in  habits,  doubtless  destroy  many  insects,  both  adult  and 
larval.  Some  of  the  larger  forms  like  the  common  mud-puppy  (Nec- 
turus),  Fig.  87,  and  the  hellbender  (Cryptobranchus),  Fig.  88,  are  also 


FIG.  89. — Spotted   salamander,    Amblystoma   punctatum.      X  M-      (From   Surface, 
First  Report  on  the  Economic  Features  of  the  Amphibians  of  Pennsylvania.) 

useful  as  scavengers  in  our  streams,  though  they  sometimes  are  a  nuisance 
to  fishermen  by  taking  their  bait.  Although  the  writer  has  made  but 
few  experiments  there  seems  to  be  no  reason  why  these  larger  salaman- 
ders should  not  be  used  as  food.  Their  flesh  looks  as  attractive  as 
that  of  the  frog  and  in  a  two-foot  giant  salamander  (Cryptobranchus) 
there  is  a  considerable  mass  of  flesh,  especially  in  the  tail,  in  a  full 
grown  Necturus  also  there  is  a  considerable  quantity  of  flesh  which 
is  very  palatable. 

The  Anura  are  by  far  the  most  important,  economically,  of  the 
Amphibia.     Of  the  various  families  of  this  order  three  will  be  noted: 


AMPHIBIA  (BATRACHIA) 


127 


the  Hylidae  or  treefrogs,  the  Ranidae  or  true  frogs  and  the  Bufonidae 
or  toads. 

The  Hylida,  Fig.  90,  are  usually  small  forms;  they  are  arboreal  in 
habits,  as  the  name  indicates,  and  as  an  aid  in  climbing  have  adhesive 
disks  at  the  ends  of  their  fingers  and  toes.  They  have  remarkable 
vocal  powers,  due  partly  to  the  presence  of  a  large  vocal  sac.  Of  the 
nearly  200  species,  more  than  a  dozen  are  found  in  North  Am- 


PIG.  90. — Tree  frog,  sp.      Xi.       Note  discs  on  toes. 

erica.  Though  doubtless  of  less  importance  than  the  other  Anura, 
these  small  frogs  probably  destroy  large  numbers  of  harmful  insects. 

The  Ranidce,  of  which  there  are  more  than  250  species,  more  than 
a  dozen  of  which  occur  in  the  United  States,  are  useful  as  destroyers 
of  insects,  as  subjects  for  dissection  and  experimental  work,  and  es- 
pecially as  an  article  of  diet. 

Almost  any  of  the  true  frogs  may  be  used  as  food,  though  many  people 
think  that  only  the  bullfrogs  are  edible.  A  simila  r  mistaken  idea  pre- 


128 


ECONOMIC   ZOOLOGY 


vails  in  the  belief  that  only  the  hind  legs  can  be  eaten,  as  a  matter  of 
fact  many  persons,  after,  skinning,  cutting  off  the  head  and  eviscerating, 
fry  the  entire  body,  perhaps  in  egg  and  bread-crumbs,  perhaps  without. 
The  main  muscles,  of  course,  are  those  of  the  hind  legs,  but  there  is  no 
sense  in  wasting  all  the  rest  of  the  body. 

Of  our  native  frogs  the  common  bullfrog,  Rana  catesbiana,  Fig.  91, 
is  the  largest  and  most  generally  known  as  an  article  of  diet;  it  may 
reach  a  length  of  8  inches  and  its  deep,  bull-like  roar  is  a  familiar 


FIG.  91. — Common  bullfrog,  Rana  catesbiana;  male.      (After  Chamberlain,  Edible 
Frogs  of  the  United  States.) 

sound  to  those  living  in  the  eastern  half  of  the  North  American  con- 
tinent. In  the  adult  condition  its  larger  size  and  massive,  clumsy 
shape  will  distinguish  it,  ordinarily,  from  the  other  common  species, 
as  will  the  presence  of  a  fold  of  skin  that  arises  back  of  the  eye,  passes 
over  the  tympanum,  past  the  insertion  of  the  foreleg,  to  disappear  on 
the  chest;  the  complete  webbing  of  the  hind  toes  and  the  absence  of 
the  dorsal  folds  of  skin  will  also  serve  to  distinguish  it.  The  color  is 
quite  variable  but  there  is  apt  to  be  a  considerable  amount  of  deep  green 
above  and  of  yellow  beneath. 

There  are  two  species  of  western  frogs  that  are  found  along  the 
coastal  States;  they  are  not  so  well  known  as  the  common  bullfrog. 


AMPHIBIA  (BATRACHIA) 


129 


A  frog  somewhat  similar  to  the  bullfrog,  both  in  appearance  and  in 
habits,  is  the  green  or  spring  frog,  R.  clamata,  Fig.  93;  it  is  much  smaller 
in  size,  however,  the  adult  measuring  only  3  inches.  Instead  of  the 
deep  bellowing  it  has  a  note  that  may  be  represented  by  the  words, 
" chock,  chock,  chock,"  and  an  occasional  single  note  "chung. "  It 
is,  in  many  places  the  first  species  heard  in  the  spring.  It  is  more  or  less 
solitary  in  habits  and  seldom  leaves  the  water.  Like  the  preceding 
species  it  passes  the  first  winter  in  the  tadpole  stage. 

The  most  widely  distributed  of  our  frogs  is  the  common  frog,  leo- 
pard frog,  spring  frog  or  shad  frog,  R.  mrescens,  Fig.  92.  It  is  found 
over  practically  the  entire  continent  east  of  the  Sierra  Nevada 
Mountains.  It  reaches  a  length  of  3^  inches  and  is  distinctly  marked 


PIG.  92. — Spring   or  leopard  frog,    Rana  virescens.       (After    Chamberlain,    Edible 
Frogs  of  the  United  States.) 

on  the  back  and  sides  and  legs  with  dark,  rectangular  blotches  bordered 
with  white  or  yellow.  A  glandular  fold  runs  from  the  eye,  along  the 
dorsal  part  of  the  side  to  the  posterior  part  of  the  body. 

The  pickerel,  marsh,  or  tiger  frog,  R.  palustris,  closely  resembles  the 
leopard  frog  from  which  it  may  be  distinguished  by  the  bright  yellow 
on  the  legs.  It  is  the  most  active  of  the  frogs  and  is  seldom  eaten. 
Though  preferring  cold  streams,  it  is  often  found  in  grass;  it  is  rather 
solitary  in  habits. 

The  flesh  of  frogs  is  best  in  the  fall  and  winter.  Later  in  the 
season,  after  prolonged  hibernation,  the  body  is  more  or  less  emaciated. 

Frogs  are  collected  for  the  market  in  large  numbers  in  California, 
Missouri,  Arkansas,  Indiana,  Ohio,  Maryland,  Virginia  and  New  York, 


130  ECONOMIC   ZOOLOGY 

especially  in  the  last,  also  in  Ontario  and  other  parts  of  Canada.  They 
are  sold  alive  and  by  the  pound,  dressed,  the  price  varying  with  the 
locality,  season  and  other  conditions. 

Frogs  are  collected  in  various  ways — a  hook  and  line,  baited  with  a 
piece  of  red  cloth  is  sometimes  dangled  in  front  of  the  frog  who  seizes 
the  moving  cloth  and  is  thus  hooked;  small  bore  fire  arms  and  various 
spears  are  also  used,  sometimes  at  night  with  a  bright  light  to  dazzle 
the  eyes  of  the  frogs;  sometimes  they  are  dug  out  of  the  mud  where  they 
are  hibernating. 

Unrestricted  hunting  has,  in  some  localities,  nearly  exterminated 
the  frogs  and  has  brought  up  the  subject  of  their  artificial  propagation. 
Without  sufficient  knowledge  of  the  breeding  habits  of  frogs  it  would 
seem  that,  with  the  high  market  values  usually  prevailing,  it  should  be 
an  easy  matter  to  make  large  profits  by  raising  them  for  market.  Part 
of  the  process  is  quite  easily  handled,  but,  as  we  shall  see,  there  is 
one  peculiarity  in  the  habits  of  frogs  that  is  difficult  to  meet.  Every- 
one is  familiar  with  the  masses  of  frog  eggs  that  are  seen  in  small  ponds 
and  sluggish  streams  in  the  early  spring;  these  may  be  collected  in  al- 
most unlimited  numbers.  In  a  few  days  or  weeks,  depending  upon  the 
temperature  of  the  water,  these  eggs  hatch  into  tiny  tadpoles  that  soon 
begin  to  feed  voraciously  upon  any  kind  of  organic  material  that  may  be 
available  and  to  grow  rapidly.  During  the  tadpole  stage  there  are 
many  enemies  such  as  birds,  snakes,  turtles,  crawfish  and  adult  frogs, 
that  destroy  these  larvae  in  large  numbers  so  that  the  first  problem  of 
the  frog  culturist  is  to  protect  in  some  way  the  eggs  and  tadpoles. 
This  may  be  done  by  collecting  the  eggs  and  allowing  them  to  hatch  and 
develop  in  artificial  ponds  or  tanks  where  the  tadpoles  may  be  fed  and 
protected,  or  better,  perhaps  by  screening  small  natural  ponds  with 
wire  netting  to  keep  out  the  above-mentioned  enemies  and  stocking 
these  ponds  with  a  number  of  adult  frogs,  males  and  females,  to  lay  the 
eggs.  In  this  way  tadpoles  without  number  may  be  raised,  but  the 
main  difficulty  mentioned  above,  arises  when  the  tadpoles  change  to 
frogs,  which  happens  in  from  two  months  to  two  years.  It  is  essential 
that  when  this  transformation  takes  place  that  the  young  frogs  or  old 
tadpoles,  whichever  they  may  be  called,  Fig.  86,  have  a  sloping  shore 
where  they  may  crawl  out  on  the  bank,  otherwise  the  metamorphosis  is 
indefinitely  postponed;  tadpoles  have  been  kept  in  aquaria  for  several 
years  without  transformation  because  of  lack  of  a  place  for  them  to  leave 


.AMPHIBIA  (BATRACHIA)  131 

the  water.  The  difficulty  that  arises  is  that  while  the  tadpole  would  eat 
anything  the  frog  will  eat  nothing  that  is  not  moving.  A  dead  insect 
on  the  ground  will  remain  untouched;  one  that  is  drifting  along  on  the 
surface  of  the  pond  will  be  seized  and  eaten.  Here,  then,  is  the  stum- 
bling block  to  the  frog  culturist,  to  supply  living  food  to  the  numberless 
young  frogs  that  he  has  obtained  so  easily.  Various  methods  have  been 
tried.  For  example  meat  was  strewn  on  the  shore  and  allowed  to  decay 
with  the  idea  that  it  would  attract  flies  and  other  insects  for  the  frogs, 
but  the  decaying  meat  is  apt  to  foul  the  water  and  kill  the  young 


FIG.  93. — Green  or  spring  frog,  Rana  clamata.      (After  Chamberlain,  Edible  Frogs 

of  the  United  States.) 

frogs  and  tadpoles.  The  only  practicable  method  seems  to  be  to  use 
natural  ponds  whose  banks  are  covered  with  a  rank  growth  of  vegetation 
that  will  supply  the  necessary  insects.  Such  a  pond  should  be  partly 
shaded  and,  of  course,  must  not  dry  up  as  summer  progresses. 

In  this  way,  by  aiding  nature  somewhat,  frogs  are  successfully 
raised  at  a  number  of  places;  for  example  in  Ontario  such  a  farm  has 
been  in  operation  for  25  years,  producing  in  one  year  as  much  as  5000 
pounds  of  dressed  legs  and  7000  living  frogs. 


132  ECONOMIC   ZOOLOGY 

It  usually  requires  three  or  four  years  for  frogs  to  reach  maturity 
and  it  is  generally  supposed  that  they  may  live  for  15  or  20  years. 

One  danger  to  eggs  and  tadpoles  that  cannot  well  be  eliminated  by 
frog  culture  is  from  late  cold  spells  that  may  freeze  the  shallow  pools 
and  kill  large  numbers  of  the  inhabitants. 

The  Bufonidce  include  over  a  hundred  species  of  toads  belonging 
chiefly  to  the  genus  Bufo;  over  a  dozen  representatives  of  this  genus 
have  been  found  in  North  America. 

The  common  toad  of  the  eastern  United  States,  Bufo  lentiginosus 
Americanus,  Fig.  94,  is  familiar  to  all  as  the  clumsy,  warty  animal  that, 


FIG.  94. — The  American  toad,  Bufo  lentiginosus  americanus.      X%. 

after  hiding  in  some  dark  nook  all  day,  hops  out,  toward  dusk,  to  seek 
his  food  during  the  night.  Being  an  ugly  animal  the  toad,  in  olden 
times  was  considered  highly  venomous,  as  noted  by  Shakespeare  and 
other  more  ancient  writers,  and  a  remnant  of  these  superstitions  is 
seen  even  now  in  the  very  common  and  entirely  erroneous  belief  that 
warts  may  be  caused  by  handling  toads.  As  a  matter  of  fact,  however, 
the  glandular  warts  so  characteristic  of  the  toad  do  secrete  a  substance 
that  protects  them  quite  largely,  from  being  eaten  as  are  the  other 
members  of  the  Urodila,  though  the  flesh  is  said  not  to  differ  appreciably 
in  taste  from  that  of  the  Ranidae. 


AMPHIBIA  (BATRACHIA)  133 

While  the  adult  toad  is  primarily  a  land  animal  and  hibernates  in 
some  cavity  under  ground,  usually  in  groups,  it  seeks  the  pools  in  early 
spring  to  spawn  as  do  the  rest  of  its  class,  laying  the  eggs  in  long, 
easily  recognized  strings,  instead  of  in  masses;  1200-1500  may  be  laid 
by  a  single  female.  During  the  breeding  season  the  toad's  call  may 
be  heard  as  a  pleasant,  tremulous  trill,  lasting  usually  about  5  or 
10  seconds.  The  development  is  about  the  same  as  that  of  the  Ranidse. 
It  is  said  that  sexual  maturity  is  not  reached  until  the  fourth  year. 
Much  has  been  conjectured  and  written  about  the  age  to  which  toads 
may  live  but  nothing  very  definite  seems  to  be  known;  it  seems  likely 
that  they  may  live  for  20  years  or  more.  Of  the  familiar  stories  of 
toads  being  found  in  the  centre  of  rocks  little  need  be  said;  a  little 
common  sense  will  show  the  absurdity  of  supposing  an  animal  could  re- 
main alive  during  the  thousands  or  millions  of  years  that  must  have 
elapsed  since  such  rocks  were  laid  down  as  sand  or  mud.  A  number  of 
actual  experiments  have  been  tried  to  test  this  oft-repeated  tale;  toads 
were  buried  in  cavities  in  the  centre  of  plaster-of-Paris  blocks  and  in 
sealed  cavities  in  rocks  of  various  sorts;  none  of  the  toads  lived  more 
than  two  years,  and  while  it  is  surprising  to  find  any  animal  living  so 
long  without  food  and  water,  two  years  is  an  infinitesimal  time  com- 
pared to  the  age  of  rocks.  The  numerous  recorded  cases  of  these 
rock-encased  toads  are  doubtless  to  be  explained  as  errors  of  observation 
or  as  pure  fabrications. 

As  has  been  said  the  toad  feeds  largely  at  night,  in  towns  often  col- 
lecting under  the  electric  lights  and  eating  the  insects  that  fall  to  the 
ground  in  large  numbers  at  such  places.  Kirkland,  who  has  carefully 
studied  the  feeding  habits  of  the  common  toad,  makes  some  interesting 
observations.  He  says  the  toad's  food  is  about  88  per  cent,  insects, 
and  1 6  per  cent,  of  these  are  cutworms;  counting  these  destructive 
cutworms  alone  he  estimates  the  annual  saving  to  the  farmer  by  each 
toad  as  nearly  20  dollars.  He  finds  that  the  toad  eats  four  stomach- 
fulls  every  24  hours;  in  three  months  this  will  amount  to  about  10,000 
insects,  a  majority  of  which  are  injurious;  slugs,  myriapods,  etc.,  are 
also  eaten;  in  fact  any  moving  animal  of  suitable  size,  even  stinging 
bees,  are  snapped  up  by  the  lightning-quick,  sticky  tongue.  By  confin- 
ing a  toad  in  an  open  box  with  syrup  or  other  sweet  substance  to 
attract  insects  its  methods  of  feeding  may  be  studied  in  an  interesting 
way. 


134  ECONOMIC   ZOOLOGY 

By  watching  the  live  toads  and  by  examination  of  the  stomach  con- 
tents of  others,  Kirkland  collected  valuable  data  in  regard  to  their 
food  at  different  seasons  and  under  different  conditions.  For  example 
during  a  pest  of  army  worms  he  found  in  one  toad's  stomach  55  of  the 
worms;  at  another  time  he  found  65  larvae  of  the  gypsy  moth  in  one 
stomach;  and  in  another  toad  were  found  37  tent  caterpillars. 

These  and  many  other  figures  might  be  given  to  show  that  as  an  in- 
sect destroyer  the  toad  probably  has  few  superiors  and  that  it  is,  perhaps, 
quite  as  valuable  as  the  average  bird  and  should  be  equally  protected 
by  law.  They  are  useful  not  only  in  gardens  but  may  be  kept  in  green- 
houses. In  a  certain  greenhouse  in  Massachusetts  a  valuable  collection 
of  orchids  was  saved  by  the  introduction  of  a  number  of  toads.  They 
should  be  collected  and  brought  into  gardens,  as  is  done  in  France, 
and  a  number  of  boards  or  stone  shelters  provided  for  them  to  creep 
under  and  escape  the  heat  of  the  sun.  Probably  if  the  garden  were  pro- 
vided with  a  small  pond  of  running  water  they  would  breed  there  and 
greatly  increase  their  numbers.  They  frequently  take  up  more  or  less 
permanent  summer  quarters  under  porches  and  other  places  to  which 
they  return  every  morning  after  the  night's  hunt. 

Their  chief  enemies  are  hawks,  crows,  and  snakes  and  from  these 
they  could  be  protected,  more  or  less,  in  gardens.  Chickens  and  ducks 
also  are  destructive  to  the  young  toads;  and  the  ubiquitous  small  boy 
who,  unless  otherwise  educated,  is  an  enemy  to  all  living  things,  is 
also  prone  to  kill  toads  of  all  ages.  Fortunately  the  toad  is  not  used 
as  an  article  of  human  food,  so  that  the  pot-hunter,  the  worst  of  all 
enemies  of  the  lower  animals,  does  not  trouble  him. 

It  will  be  seen,  then,  that  practically  all  of  the  Amphibia  are  of 
some  value  to  man  and  that  few  if  any  of  them  are  harmful  in  any  way. 


CHAPTER  XII 
REPTILIA 

Reptilia  are  cold-blooded  vertebrates  with  an  epidermal  skeleton  of 
scales,  and  often  with  an  armor  of  bony  dermal  plates.  They  never 
breathe  by  gills  and  do  not  have  the  tadpole  stage  seen  in  the  Amphibia. 
Many  of  them  lay  eggs  of  a  large  relative  size,  inclosed  in  a  leathery  or 
a  calcareous  shell.  The  centra  of  the  vertebrae  have  spheroidal  articu- 
lar surfaces.  There  is  one  occipital  condyle  and  the  mandibles 
usually,  and  other  bones  frequently,  bear  teeth.  The  ventricles  of  the 
heart  are  usually  incompletely  separated  and  there  are  always  two 
aortic  arches  in  the  adult. 

The  reptiles,  though  clearly  distinguished  from  them  by  having 
cold  instead  of  warm  blood  and  scales  instead  of  feathers,  are  closely 
related  to  the  next  class,  the  birds,  with  whom  they  are  frequently 
grouped  under  the  name  Sauropsida.  In  the  same  way  the  reptiles, 
birds  and  mammals,  since  they  all  possess  the  embryonic  structure 
known  as  the  amnion,  are  ground  together  under  the  name,  Amniota. 

During  the  Mesozoic  period  the.  rep  tiles  reached  their  maximum, 
both  as  to  numbers  and  individual  size,  so  that  this  period  is  often 
spoken  of  as  the  "age  of  reptiles;"  the  largest  of  the  living  reptiles  are 
pygmies  compared  to  the  huge  individuals  of  this  age. 

The  reptilia  are  variously  classified  by  different  authors,  being  di- 
vided into  from  nine  to  fifteen  or  more  orders.  Of  these  orders,  four 
include  the  4000  or  more  species  of  living  forms,  which,  of  course, 
are  the  only  ones  of  economic  importance  except  as  mere  specimens, 
or  as  determiners  of  geological  horizons. 

The  four  orders  of  living  reptilia  are  as  follows: 

i.  Chelonia  or  Testudinata. — These  forms  are  easily  recognized  by 
the  bony  or  leathery  carapace  covering  the  dorsal  side  of  the  body  and 
a  flat  plastron  on  the  ventral  side;  these  bones  are  usually  covered  with 
horny  epidermal  plates;  the  appendages  are  clawed  and  adapted  for 
use  on  land,  or  are  paddle-like  for  use  in  swimming.  The  jaws  are 
armed  with  sharp  bony  edges  instead  of  teeth;  tympanic  membranes 


136  ECONOMIC   ZOOLOGY 

and  movable  eyelids  are  present.     These  are  the  familiar  and  easily 
recognized  turtles,  terrapins  and  tortoises. 

2.  The  Squamata. — The  characteristics  of  this  order,  as  a  whole, 
are  largely  osteological  so  that  we  shall  consider  at  once  the  two  sub- 
orders of  living  Squamata,  which  are  sometimes  considered  as  distinct 
orders;  they  are  the  Lacertilia  and  the  Ophidia.     The  former  are  usually 
provided  with  legs  for  walking;  nearly  always  with  eyelids  and  tympanic 
membranes;  the  rami  of  the  mandibles  are  closely  united  at  the  sym- 
physis  and  the  mouth  can  open  only  moderately  widely;  a  sternum  is 
present;  they  are  represented  by  the  various  lizards,  such  as  Geckos 
Iguanas,  Chameleons,  etc.     The  latter  sub-order,  the  Ophidia,  are  the 
snakes  they  are  much  elongated  forms  without  appendages,  movable 
eyelids,  tympanum  and  sternum;  the  rami  of  the  mandibles  are  con- 
nected by  elastic  fibres,  and  the  mouth  can  be  opened  to  an  extraor- 
dinary width. 

3.  The  Crocodilia. — The  body  is  here  more  or  less  covered  with 
bony  scales;  a  sternum  is  present  and  also  a  set  of  abdominal  ribs: 
the  Cloaca  is  longitudinal  in  position  and  sheaths  a  medium  penis; 
the  legs  are  adapted  for  walking  and  the  tail  is  usually  compressed  for 
swimming;  the  teeth  are  numerous  and  held  in  sockets;  the  ventricle 
of  the  heart,  in  living  species,  is  completely  divided.     This  order  in- 
cludes as  living  representatives  the  familiar  crocodiles  and  alligators 
and  also  the  gavials  and  caimans,  some  of  which  are  the  giants  of  the 
present  reptilian  world. 

4.  Rhynchocephalia. — This  order  is  represented  by  a  single  living 
genus   Hatteria   or   Sphenodon;   a  lizard-like  reptile  found  in  New 
Zealand.     Since  its  only  economic  importance  is  as  a  specimen  no 
further  description  will  be  given  here. 

Chelonia  or  Testudinata. — The  Chelonia  are,  by  some,  divided  into 
three  groups,  the  turtles,  the  terrapins,  and  the  tortoises,  this  division 
being  based  chiefly  upon  the  habitat  of  the  species,  whether  terrestrial, 
aquatic  or  amphibious.  As  these  names  are  employed  differently  by 
different  authors  and  in  different  sections  of  the  world,  no  attempt  will 
be  made  here  to  distinguish  between  them,  and  the  word  turtle  will  be 
generally  used  for  any  member  of  the  order. 

It  is  as  food  for  man  that  the  chelonia  are  chiefly  important,  though 
there  are  other  economic  aspects  of  the  group  that  will  be  briefly 
discussed. 


REPTILIA  137 

Turtles  are  used  for  food  over  practically  the  entire  world,  but,  it  is 
said,  their  flesh  is  forbidden  to  Mohammedans,  and  is  abhorred  by  cer- 
tain Greeks. 

Nearly,  if  not  all,  species  may  be  eaten,  but  there  is,  of  course,  much 
difference  in  the  quality  of  the  flesh,  and  Surface  (136)  states  that  during 
a  strike  of  miners  in  eastern  Pennsylvania  many  of  them  were  made 
sick  by  eating  turtles,  supposedly  the  box  tortoise,  so  that  the  common 
idea  that  this  form  is  inedible,  at  least  at  certain  seasons,  is  probably 
correct.  There  are  also  a  few  species  whose  offensive  odor  makes  them 
undesirable  as  food.  It  is  said  that  even  the  flesh  of  the  Green  Turtle, 
about  to  be  described,  is  poisonous  at  certain  seasons  of  the  year  in 
some  countries  where  it  is  found. 

The  Green  Turtle,  Chelone  mydas,  Fig.  95. — This  is,  perhaps,  the 
most  important  of  the  turtles  as  an  article  of  food;  it  is  an  important 
article  of  commerce,  and  is  an  important  part  of  the  diet  of  some  of  the 
tropical  peoples.  It  is  found  in  tropical  and  semitropical  seas  through- 
out the  world,  and  may  reach  a  weight  of  500  pounds,  though  these 
huge  ones  are  not  so  good  for  food;  those  found  in  markets  usually 
weigh  from  50  to  75  pounds.  The  name  has  been  given  because 
of  the  green  color  of  the  flesh.  Jamaica  was  formerly,  and  perhaps 
still  is,  one  of  the  chief  centres  for  the  Green  Turtle  industry;  Key 
West  has  also  been  an  important  centre.  In  one  year  15,000  animals 
were  received  into  England,  besides  a  large  amount  of  dried  meat  in  cans, 
the  meat  for  canning  being  cut  into  strips  and  dried  in  the  sun,  where  it 
acquires  almost  the  consistency  of  glue  and  requires  long  soaking  in  water 
before  it  is  fit  for  food.  About  1900  the  turtle  trade  of  Jamaica 
amounted  to  about  $50,000,  and  the  demand  was  greater  than  the 
supply. 

As  in  many  other  turtles  the  oil  may  be  extracted  and  used  for 
culinary  purposes  in  place  of  butter  or  olive  oil. 

In  markets  these  turtles  are  kept  lying  on  their  backs  not  only  to 
keep  them  from  escaping  but  because,  being  adapted  to  life  in  the  water, 
they  would  not  be  able  to  breathe  if  laid  upon  a  hard  surface,  right  side 
up;  their  plastron  is  not  firm,  like  that  of  a  land  form,  and  the  weight 
of  the  animal,  when  not  supported  by  the  surrounding  water,  so  com- 
presses the  internal  organs  that  suffocation  may  be  produced.  The 
flesh  may  be  cooked  in  various  ways,  and  is  said  to  be  very  digestible. 

The  Green  Turtle  lays  from  200  to  300  leathery-shelled  eggs  that  are 


138 


ECONOMIC   ZOOLOGY 


REPTILIA  139 

more  nutritious  than  hen's  eggs;  a  dozen  of  them  may  be  eaten  at 
once.  The  eggs,  which  are  carefully  buried  and  concealed  by  the 
female,  are  found  by  prodding  in  the  sand,  along  the  shore,  with  a 
sharp  stick. 

Owing  to  the  decrease  in  their  numbers  it  has  been  suggested  that 
these  turtles  be  artificially  propagated;  it  is  thought  they  would  reach  a 
marketable  size  in  three  years. 

Along  the  Amazon  and  Orinoko  Rivers  the  eggs  of  various  turtles 
form  a  very  important  article  of  food;  they  are  preserved  by  rolling  and 
packing  in  salt,  an<jin  other  ways.  A  kind  of  oil,  much  esteemed  by  the 
natives,  is  made  from  them,  preserved  in  jars,  and  used  like  butter. 
The  collection  of  such  enormous  numbers  of  eggs  has  nearly  extermin- 
ated the  apparently  limitless  numbers  of  turtles  in  some  places.  The 
eggs  of  many  of  our  common  fresh-water  turtles  are  good  as  food 
if  taken  from  the  animal  or  obtained  soon  enough  after  being  laid. 

The  Loggerhead  Turtle,  Thalassochelys  caretta. — This  is  another 
large,  marine  form,  somewhat  similar  to  the  preceding  that  is  sometimes 
found  in  the  markets,  though  it  is  of  much  less  value. 

The  Diamond-back  Terrapin,  Malacoclemmys  palustris,  Fig.  96. — 
This  species  is  supposed  to  be  the  most  delectable  of  all  the  turtles. 
It  is  a  comparatively  small  animal,  seldom  exceeding  a  length  of 
7  inches,  that  is  found  in  the  salt  marshes  of  our  coast,  from 
Massachusetts  to  Texas,  those  of  Chesapeake  Bay  being,  perhaps,  the 
most  famous.  It  has  been  named  because  of  the  angular  areas  made  by 
the  concentric  lines  on  the  carapace. 

The  diamond-backs  hibernate  .by  burying  themselves  in  the  mud 
along  the  shore,  whence  they  are  tracked  and  dug  out  for  sale  in  the 
markets.  Their  rarity  and  comparatively  small  size,  combined  with 
their  unusual  flavor,  cause  these  turtles  to  be  among  the  most  expen- 
sive of  our  food  products.  A  single  animal  of  7  inches  length  is 
worth  about  $6,  and  the  price  increases  at  the  rate  of  about  $i 
for  each  additional  half  inch  in  length;  a  7-inch  specimen  weighs 
about  4  pounds. 

At  such  prices  it  would  seem  highly  profitable  to  raise  these  turtles 
under  artificial  conditions.  The  experiment  has  been  and  is  still 
being  tried,  but  the  slow  growth  of  the  animals  and  the  small  number  of 
eggs  produced  each  year  make  the  enterprise  a  doubtful  one  from  a 
financial  point  of  view. 


140 


ECONOMIC   ZOOLOGY 


The  only  diamond-back  terrapin  farm  that  the  author  has  visited, 
may  be,  as  claimed,  the  only  one  in  existence.  It  is  operated  by  Mr. 
A.  M.  Barbee  at  the  Isle  of  Hope,  a  suburb  of  Savannah,  Georgia. 
At  this  farm  may  be  seen  terrapin  by  the  thousands,  awaiting  shipment 
to  hotels  and  restaurants  of  the  larger  cities.  Not  only  are  the  live 


FIG.  96. —  Carapace    of   diamond-back  terrapin,  Malacocelemmys  palustris  (Mala- 
clemmys  canlratd).      X%. 

terrapin  shipped  but  they  are  preserved  in  jars  and  sold  in  this  more 
convenient  form. 

The  butts,  cows  and  heifers,  as  they  are  called,  are  kept  in  separate 
pens,  except  during  the  breeding  seasons,  and  the  sick  animals  are 
isolated  until  their  recovery  or  death.  The  death-rate  at  the  farm  is 
said  to  be  extremely  low.  The  following  facts  were  obtained  directly 


REPTTLIA  141 

from  Mr.  Barbee  and  from  a  small  book  that  he  has  prepared;  the  book 
is  here  quoted  freely.  "The  terrapin  are  divided  into  three  sizes. 
The  largest  are  known  as  the  count  and  measure  about  6j^  inches. 
The  next  are  known  as  the  halves  and  measure  about  5^  inches. 
These  are  the  fine  marketable  terrapin  and  can  always  be  counted 
upon  to  bring  fancy  prices.  There  is  also  a  smaller  size  known 
as  the  quarter,  which  is  also  a  very  good  table  terrapin.  The  greater 
demand  is  always  for  the  larger  terrapin,  though  the  smaller  ones  are 
tenderer  and  sweeter."  The  length  is  taken  from  the  lower  shell 
or  plastron. 

"The  demand  for  terrapin  is  now  very  small  south  of  Baltimore. 
Atlanta,  Macon  and  other  cities  in  the  neighboring  states  usually 
purchase  a  dozen  or  so  off  and  on  during  the  winter  to  supply  the 
demand  of  tourists,  but  there  is  very  little  terrapin  eaten  by  the  south- 
ern whites.  It  is  said  that  before  the  Civil  War  the  slaves  along  the  coast 
countries  were  fed  upon  them  extensively.  With  the  growing  scarcity 
of  the  diamond  backs  the  French  chefs  are  now  said  to  be  trying  to 
induce  the  proprietors  of  the  hotels  to  purchase  the  cheaper  terrapin, 
promising  that  when  they  are  through  with  cooking  them  the  guests 
will  not  know  the  difference.  But  a  man  with  any  taste  can  easily 
tell  when  the  flavor  of  the  diamond  back  is  missing.  There  are  very 
few  of  the  present-day  cooks  who  can  prepare  a  bowl  of  the  famous  dish. 
Diamond-back  terrapin  stew  costs  the  consumer  at  the  rate  of  $2.00  a 
plate  in  the  larger  cities." 

The  farm  on  which  the  terrapin  are  fattened  and  kept  ready  for 
prompt  shipment  is  150  feet  long  and  60  feet  in  width.  It 
is  roofed  and  securely  enclosed  against  invaders,  but  is  so  open 
that  it  is  perfectly  ventilated.  The  entire  place  may  be  flooded  at 
will.  The  pens  or  crawls  are  always  flooded  with  salt  water  to  a  depth 
of  4  feet  when  the  terrapins  are  fed,  usually  about  three  times  a 
week  in  the  warmer  seasons  and  not  at  all  during  the  winter  hibernation, 
when  the  animals  bury  themselves  deep  in  the  sand.  The  water  is 
pumped  in  from  the  river  and  in  a  few  hours  all  the  terrapin  are  swim- 
ming, they  feed  better  in  the  water.  .  After  the  animals  have  finished 
eating,  the  water  is  run  out  of  the  pens.  Shrimp,  fiddler  crabs,  fish, 
lettuce,  celery,  etc.,  are  used  in  feeding.  Fresh  water  is  kept  running 
through  a  trough  in  the  centre  of-  all  of  the  18  pens  into  which 
the  farm  is  divided.  The  pens  are  sunk  several  feet  below  the  level 


142 


ECONOMIC   ZOOLOGY 


REPTILIA  143 

of  the  ground  to  prevent  the  terrapin  from  digging  out.  A  foundation 
of  brick  was  abandoned  because  the  terrapin  scratched  at  them  until 
they  wore  away  their  claws.  For  the  winter  trade  the  terrapin  must  be 
dug  out  of  the  sand,  sometimes  from  a  considerable  depth. 

"The  trouble  in  raising  terrapin  heretofore  has  always  been  that 
the  animals  in  confinement  will  invariably  eat  their  own  eggs.  It 
was  many  years  before  I  was  able  to  overcome  this  trouble.  Even 
after  I  had  perfected  an  incubator  I  could  not  fill  them  because  the  eggs 
were  either  destroyed  or  were  scattered  all  over  the  pens,  buried  out  of 
sight,  sometimes  at  some  little  depth,  which  necessitated  spading 
up  the  entire  farm  each  day  to  secure  them.  This  process  was  so  dis- 
turbing to  the  terrapin  that  it  was  abandoned.  One  day  after  feeding, 
a  hillock  of  sand  was  left  in  one  of  the  pens  by  the  receding  water.  The 
following  morning  I  found  this  hillock  literally  sown  with  fresh  eggs. 
I  have  since  learned  that  terrapin  always  seek  elevations  in  which  to 
deposit  their  eggs.  Now  hillocks  of  sand  are  carefully  prepared  and 
maintained  in  each  of  the  breeding  pens.  I  have  only  to  turn  the 
sand  over  with  my  hands  to  uncover  the  eggs."  Three  sets,  with 
eight  or  ten  eggs  in  each  set,  are  laid  by  a  female  in  June,  July  and 
August. 

"Artificial  incubation  of  terrapin  eggs  has  heretofore  been  consid- 
ered an  impossibility.  Every  incubator  is  carefully  marked  with  the 
date  when  the  eggs  are  expected  to  hatch.  There  are  now  30  in- 
cubators on  the  farm.  Incubation  in  the  hatcheries  requires  approxi- 
mately 12  weeks'  time  which  is  about  twice  as  long  as  would  be 
necessary  under  normal  conditions." 

The  incubator  consists  of  shallow,  wooden  trays  divided  into  com- 
partments and  filled  with  sand  and  humus  in  which  the  eggs  are  buried. 

Terrapin  are  hatched  in  the  fall  of  the  year  and  should  be  allowed 
to  stay  in  the  sand.  The  mother  terrapin  never  looks  after  her  young. 

"Most  of  our  young  terrapin  are  placed  in  enclosed  marshes  and 
allowed  to  grow  and  look  after  themselves.  The  age  of  a  terrapin  is 
hard  to  guess.  After  they  get  to  the  size  of  6^  inches  they.are  full 
grown.  The  male  terrapin  only  grows  to  be  4^  inches. "  The  enclosed 
marshes  are  surrounded  by  wire  netting  and  are  guarded  by  paid  keepers, 
but  as  they  are  located  some  miles  distant  from  the  farm  they  were 
not  visited  by  the  writer. 

"It  is  hard  to  believe  that  these  ungainly  creatures  would  exhibit 


144  ECONOMIC   ZOOLOGY 

any  intelligence.  They  know  me,  however,  as  a  dog  knows  his  master. 
I  have  a  peculiar  clucking  sound  with  which  I  call  them.  They  will 
also  respond  to  a  whistle.  The  terrapin  will  crawl  over  my  feet  and 
almost  up  my  leg  to  reach  their  food.  They  will  also  come  when  I 
wave  a  handkerchief.  It  is  a  rather  flesh-creeping  sensation  to  hear 
the  claws  of  5000  terrapin  scraping  over  firm  sand.  From  any- 
body except  me  the  terrapin  will  flee.  He  is  one  of  the  shyest  of  crea- 
tures. A  little  noise  will  confuse  and  terrify  him  readily.  I  once  went 
into  the  pens  wearing  a  new  suit  of  clothes  and  a  new  pair  of  shoes. 
I  was  very  much  surprised  to  see  my  pets  fleeing  in  panic  from  me  in 
all  directions." 

The  pens  are  guarded  at  night  against  thieves  by  a  number  of  dogs. 
These  dogs  and  the  terrapin  soon  become  so  accustomed  to  each 
other  that  they  live  together  in  perfect  peace  and  harmony.  The 
terrapin  should  be  killed  by  amputation  of  the  head,  not  by  immersion 
in  boiling  water,  as  is  often  said,  and  various  precautions  in  dressing 
and  cooking  the  meat  should  be  taken  in  order  to  secure  the  best  flavor. 

The  Common  Snapping  Turtle,  Chelydra  serpentina,  Fig.  97. — This 
familiar  chelonian  inhabits  ponds  and  slow-running  streams  of  the 
United  States  east  of  the  Rockies.  It  sometimes  weighs  as  much  as 
40  pounds  and  is  named  from  its  habit  of  snapping  at  any  annoying 
object  with  such  vigor  that  human  finger  may  be  amputated  by  a  mod- 
erate-sized specimen.  They  are  sold  in  large  numbers  in  some  of  the 
greater  cities  and  bring  about  10  cents  a  pound. 

The  food  of  the  snapper  consists  of  all  sorts  of  animal  matter,  and 
it  is  sometimes  very  destructive  to  ducks  and  other  water  fowl,  destroy- 
ing entire  broods  of  the  young  birds.  Should  the  snapper  become  a 
pest  in  the  duck  pond  it  may  be  caught,  according  to  Surface,  by  baiting 
a  strong  fish-hook  with  a  piece  of  tainted  meat  and  tying  the  line  to  a 
slender  stake  or.  tree  that  will  bend  when  the  turtle  pulls.  The  hook 
must  be  fastened  to  the  line  by  a  length  of  slender  wire  so  that  the  turtle 
cannot  bite  it  off  and  escape. 

In  ,its  feeding  habits,  then,  it  is  probable  that  the  snapper  is  more 
harmful  than  beneficial;  the  birds,  frogs  and  fish  it  destroys  more  than 
making  up  for  the  insects  and  other  pests  that  it  eats. 

The  Soft  SheUed  Turtles,  Genus  Trionyx,  Fig.  98.  There  are  several 
species  of  soft  shelled  turtles  in  the  United  States,  and  while  they  are 
differently  named  by  different  writers  they  may  all  be  recognized  by 


REPTILIA 


145 


10 


146 


ECONOMIC  ZOOLOGY 


the  soft,  leathery  character  of  the  shell,  and  by  the  proboscis-like  snout. 
They  are  thought  by  some  to  be  the  most  palatable  of  all  our  turtles 


FIG.  98. — Common  soft-shelled  turtle,  Aspidonectes  spinifer;  dorsal  and  ventral 
views,  and  lateral  view  of  head.  ^.  (After  Surface,  Economic  Features  of  Turtles 
of  Pennsylvania.) 

with  the  exception  of  the  diamond-back,  and,  as  a  large  specimen  may 
reach  a  length  of  18  inches,  they  furnish,  in  some  sections,  quite 
a  valuable  supply  of  food. 


REPTILIA  147 

Their  omnivorous  habits  make  it  difficult  to  determine  their  eco- 
nomic importance  in  this  regard.  It  is  said  they  are  very  destructive  to 
fish  and  water-fowl  in  some  regions;  on  the  other  hand  they  may  do  an 
important  work  as  scavengers  and  as  destroyers  of  insects.  Many  of 
them  are  savage  in  disposition  and  their  jaws  are  capable  of  inflicting 
ugly  wounds.  Most  of  them  are  strictly  aquatic  in  habits,  being  found 
in  ponds  arid  muddy  streams,  which  they  seldom  leave. 

The  Common  Box  Turtle,  Cistudo  (Terrapene)  Carolina. — This  very 
variable  but  well-known  animal  is  the  slow,  plodding  tortoise  that  is 
found  in  gardens  and  fields  all  over  the  Eastern  States.  It  is  a 
gentle,  harmless  animal,  as  though  it  realized  that  its  tightly  closing 
shell  afforded  such  perfect  protection  that  offensive  actions  on  its  part 
were  unnecessary.  As  stated  above  it  is  probably  not  fit  for  food  so  that 
its  economic  importance  depends  upon  its  feeding  habits.  Its  food 
consists  of  berries  and  other  vegetable  matter,  including,  it  is  said  by 
some,  melons;  also  insects  and  other  small  animals.  It  is  thought  by 
Surface  that  the  destruction  of  cantaloups  on  their  vines  is  more  than 
paid  for  by  the  destruction  of  insect  pests,  so  that  this  species  is  a  friend 
to  the  farmer  and  should  be  protected. 

Among  the  chelonia  that  are  of  less  economic  importance  are  the 
Musk,  Map,  Red-bellied,  Speckled,  and  Wood  Turtles.  While  most  of 
these  are  used  for  food,  to  some  extent,  they  are  all,  according  to  the 
investigations  of  Surface,  probably  of  benefit  as  insect  destroyers  or 
scavengers  or  both. 

Other  more  or  less  well-known  forms  are  perhaps  neither  very 
useful  nor  especially  harmful  to  the  interests  of  man.  In  some  cases  so 
little  is  known  of  their  habits  that  it  is  impossible  to  form  an  opinion 
of  their  economic  importance. 

As  subjects  for  dissection  and  experimentation  almost  any  of  the 
common  chelonia  have  a  certain  value  and  there  are  several  firms  that 
keep  them  regularly  in  stock  to  sell  to  colleges  and  other  institutions. 

The  fresh-water  turtles  that  are  used  for  food  or  for  scientific 
purposes  are  captured  in  various  ways.  Many  of  them  are  taken, 
sometimes  scores  in  a  day,  by  digging  them  out  of  the  mud  or  sand  in  the 
bottom  or  along  the  shores  of  the  ponds  or  streams  in  which  they  live. 
At  the  approach  of  winter  they  bury  themselves  in  these  places  and 
hibernate  until  spring.  With  a  pointed  and  barbed  rod  the  hunter 
prods  into  the  mud  and  on  feeling  a  turtle  pulls  it  up  with  the  rod. 


148  ECONOMIC   ZOOLOGY 

Turtles  are  also  caught  on  a  line  baited  with  meat,  as  mentioned  above. 
In  the  case  of  the  soft-shelled  turtle  the  meat  is  kept  near  the  surface 
by  a  cork.  Wire  traps,  with  funnel-shaped  entrances  like  fish  traps,  are 
often  used  and  are  baited  with  ears  of  corn  that  become  sour  and  attract 
the  turtles.  Such  traps  must  be  examined  at  moderately  frequent 
intervals  or  the  turtles  may  drown.  The  collection  of  fresh-water 
turtles,  in  some  sections,  is  quite  an  important  industry. 

It  is  seen,  then,  that  most  of  our  fresh-water  chelonia  are  of  im- 
portance to  man,  either  as  food,  as  scavengers,  as  insect-destroyers,  or  as 
subjects  for  scientific  work. 

The  Hawksbill  Turtle,  Chelone  imbricata,  Fig.  99. — It  is  from  this 
form,  the  smallest  of  the  marine  turtles,  that  the  "tortoise  shell,"  so 
valued  when  made  into  combs  and  other  small  articles,  is  obtained. 
A  large  specimen  is  about  30  inches  long  and  may  be  recognized  by 
the  overlapping  epidermal  plates.  There  are  thirteen  of  these  large 
plates,  which  are  rarely  over  an  eighth  of  an  inch  thick;  a  large  animal 
will  yield  about  8  pounds.  These  plates,  which  are  the  "  tortoise 
shell,"  are  removed  by  holding  the  animal  over  a  fire  or  by  immersing 
it  in  hot  water.  It  is  said  that  the  natives  of  the  tropics  sometimes  re- 
move the  plates  from  the  living  animal,  which  is  then  set  free  to  regen- 
erate a  new  set  of  plates.  This  cruel  expedient  is  of  no  avail  as  the 
regenerated  plates  are  probably  of  no  commercial  value. 

The  thin  plates  are  softened  and  worked  at  about  100°  C.  and  are 
welded  together  with  hot  irons  into  layers  of  the  desired  thickness. 
Real  shell  generally  shows  the  fine  lines  where  the  plates  were  welded 
together,  but  there  are  so  many  and  such  perfect  imitations  of  tortoise 
shell  that  but  few  people  are  able  to  tell  the  real  article  from  the  best 
imitations. 

India,  China,  Japan  and  the  West  Indies  are  among  the  great 
centres  for  this  article  of  commerce.  The  artificial  rearing  of  this 
turtle  also  has  been  suggested. 

Lacertilia. — As  pointed  out  in  the  preceding  chapter  the  lizards 
and  salamanders  are  seldom  distinguished  in  the  popular  mind,  all 
being  alike  called  "lizards."  In  some  sections  the  lizards  are  called 
"scorpions,"  though  how  this  misnomer  should  have  come  about  is 
hard  to  understand. 

Another  misconception  that  should  be  corrected  is  the  very  general 
belief  in  the  poisonous  character  of  the  common  lizards.  As  a  matter  of 


REPTILIA 


149 


150  ECONOMIC   ZOOLOGY 

fact  all  of  our  lizards  are  entirely  harmless  with  the  exception  of  the 
beaded  lizards,  of  Mexico  and  the  extreme  southwestern  part  of  the 
United  States,  to  be  described  below. 

In  studying  the  lizards  of  Pennsylvania,  Surface  found  no  vegetable 
food  in  any  of  the  stomachs  examined.  It  is  probable  that  the  food 
of  our  common  lizards,  Fig.  100,  consists  largely  of  insects,  and  that 
they  do  a  great  amount  of  good  in  destroying  these  pests  and  hence 
should  be  protected  everywhere.  Some  species  seem  especially  fond  of 
grasshoppers. 

The  Beaded  Lizards,  Heloderma  suspectum  and  H.  horridum. — As 
noted  above  these  lizards  are  the  only  ones  on  this  continent,  so  far  as  is 
known,  that  are  venomous.  Southern  Arizona  and  New  Mexico  is 
the  habitat  of  the  first  species;  western  Mexico  and  Central  America  of 
the  second.  The  former,  known  as  the  Gila  (pronounced  Heela) 
Monster,  may  be  seen  in  many  of  our  zoological  parks,  and  reaches  a 
length  of  1 8  to  24  inches.  While  tame  and  good-natured  in  captivity, 
it  is  said  to  be  of  a  very  different  disposition  in  its  native  environment, 
and  strange  tales  are  told  of  its  ferocity  and  of  its  tenacity  of  grip. 
Its  poison  fangs  are  in  its  lower  jaw  and  it  is  commonly  said  that  it 
turns  upon  its  back,  in  biting,  to  cause  the  poison  to  flow  into  the  wound; 
whether  or  not  this  be  true  the  writer  is  not  able  to  say. 

There  is  considerable  difference  of  opinion  as  the  effect  of  the  bite 
of  the  Gila  Monster,  some  claiming  it  to  be  very  deadly  to  human  beings, 
others  holding  the  opinion  that  it  has  but  little  effect  upon  man.  Dit- 
mars  is  of  the  opinion  that  the  beaded  lizards  are  "dangerously  poi- 
sonous to  man."  Being  easily  recognized  by  the  bead-like,  brightly 
colored  skin  and  club-shaped  tail  there  is  no  reason  for  confusing  these 
with  the  harmless  lizards,  and  their  restricted  range  makes  them  of  no 
importance  to  the  vast  majority  of  our  people.  Even  in  their  native 
range  they  are  so  scarce  that  the  writer  wandered  many  miles  over  the 
Arizona  desert  searching  in  vain  for  a  single  specimen. 

It  is  probably  safe  to  say,  then,  that  all  of  our  lizards,  with  the  ex- 
ception of  the  two  species  just  described,  are  not  only  entirely  harmless 
to  man  and  to  vegetation  but  that  they  are  highly  useful  as  insect 
destroyers. 

In  many  tropical  countries  both  the  lizards  themselves  and  their 
eggs  are  largely  used  as  food.  It  is  the  huge  Iguanas,  Fig.  101,  reaching 
a  length  of  six  or  more  feet,  that  are  chiefly  used  in  this  way.  The  flesh  is 


REPTILIA 


152 


ECONOMIC   ZOOLOGY 


REPTILIA  153 

said  to  be  of  delicious  flavor,  resembling  chicken.  In  the  Bahamas  the 
lizards  were  formerly  one  of  the  most  important  articles  of  food;  they 
were  hunted  with  dogs  and  kept  in  captivity  till  wanted.  They  have 
been  hunted  almost  to  the  point  of  extermination  in  some  places. 

Ophidia. — Of  all  the  vertebrates  the  Ophidia  or  serpents  are  probably 
the  most  universally  and  undeservedly  hated  by  man. 

While  not  one  of  the  more  important  groups  economically  the 
Ophidia  have  sufficient  importance  to  warrant  some  discussion,  and 
the  majority  are,  to  say  the  least,  quite  harmless  and  inoffensive. 

Dividing  the  Ophidia  into  two  main  groups,  the  venomous  and  non- 
venomous  snakes,  it  will  be  found  that  the  former  is  much  the  smaller 
group  and  it  will  be  discussed  first. 

It  is  generally  said  that  all  of  the  venomous  snakes  of  the  United 
States  are  included  among  the  rattlesnakes,  the  copperhead,  the  moc- 
casin, and  the  coral  snakes;  but,  according  to  some  authors,  the  so- 
called  opisthoglyph  snakes  should  be  included  among  the  venomous 
serpents.  As  indicated  by  the  name,  the  opisthoglyph  snakes  have 
their  poison  fangs,  which  are  small  and  grooved,  in  the  rear  part  of 
the  upper  jaw,  so  that  a  person  may  be  bitten  by  one  of  these  snakes 
without  being  pierced  by  the  poison  fangs  and  hence  without  unpleas- 
ant results.  Some  of  these  snakes  are  too  small  to  have  any  effect 
upon  man,  others  are  large  enough  to  produce  unpleasant  though  prob- 
ably not  serious  results.  They  are  found  only  in  the  far  south  espe- 
cially along  the  southern  borders  of  Texas,  Arizona,  and  New  Mex- 
ico. So  far,  then,  as  the  vast  majority  of  the  people  of  the  United 
States  are  concerned  the  venomous  serpents  are  included  among  those 
mentioned  above,  and  it  is  a  very  simple -matter  to  distinguish  these 
few  from  the  much  greater  number  of  harmless  ones.  The  idea  that 
several  of  our  common  and  harmless  snakes  are  venomous  is  so  deep 
rooted  that  it  is  difficult  to  make  people  believe  otherwise. 

Of  the  really  venomous  forms  the  Elapine  snakes  are  the  rarest. 
They  include  two  beautiful  snakes  in  this  country,  the  Harlequin  or 
Coral  Snake  of  the  southern  states  and  the  rare  Sonora  Coral  Snake  of 
southern  Arizona  and  Sonora,  Mexico.  Both  snakes  belong  to  the 
genus  Elaps,  and  are  related  to  the  deadly  Cobras  of  the  Orient. 

The  Harlequin  Snake,  Elaps  fulvius. — This  is  a  comparatively 
small,  slender  snake,  rarely  reaching  a  length  of  a  yard.  It  is  found 
from  North  Carolina  through  the  Gulf  States  into  Central  America. 


154 


ECONOMIC   ZOOLOGY 


In  the  Mississippi  Valley  it  may  be  found  as  far  north  as  southern 
Ohio.  It  is  strikingly  colored  with  transverse  scarlet  and  black  bands, 
separated  by  narrow  yellow  bands.  It  is  strikingly  similar  in  its  colora- 
tion to  the  harmless  Scarlet  King  Snake,  but  in  the  latter  the  black 
bands  border  the  yellow,  instead  of  the  yellow  bordering  the  black. 
It  has  a  small  head,  with  an  indistinct  neck,  and  is  more  or  less  subter- 
ranean in  habits.  Its  pupils  are  round  like  those  of  the  nonvenomous 
snakes. 

Just  how  serious  to  man  is  the  bite  of  the  Coral  Snake  it  is  difficult 
to  say;  Ditmars  thinks  that  in  spite  of  its  small  fangs  "It  should  be 

placed  in  the  list  of  dangerously 
poisonous  snakes,"  but  its  striking 
coloration  and  secretive  habits  cause 
it  to  be  of  little  danger  to  man  even 
within  its  rather  restricted  range. 

The  Viperine  Snakes,  or  pit  vipers 
include  the  well-known  and  widely 
distributed  venomous  snakes,  the 
Rattlers,  the  Copperheads,  and  the 
Moccasins.  These  are  all  thick- 
bodied  forms,  with  flat,  triangular 
heads,  distinct  necks,  elliptical  (not 
circular)  pupils,  and  with  the  highly 
characteristic  "pit"  between  the  eye 
and  the  nostril.  This  pit,  Fig.  102, 
whose  function  is  unknown,  is  large 

enough  in  probably  all  cases  to  be  seen  at  a  greater  distance  than  its 
owner  is  able  to  strike  (as  a  rule  a  snake  can  strike  only  one-half  or 
two-thirds  of  its  length),  and  may  be  taken  as  a  sure  sign  that  its 
possessor  is  venomous. 

The  fangs  of  these  vipers  consist  of  a  large,  curved,  hollow  tooth  near 
the  front  of  the  upper  jaw  on  either  side,  Fig.  103.  Strange  as  it  may 
seem,  many  people  call  the  forked,  quivering  tongue  the  fang;  what- 
ever function  or  functions  the  tongue  may  have,  it  is  perfectly  harmless. 
The  fangs  are  surrounded  by  sheaths  of  soft  tissue,  and  when  the  mouth 
is  closed  they  lie  up  against  the  upper  jaw,  with  the  needle-like  point 
toward  the  rear;  the  sheaths  almost  hide  the  fangs,  even  when  they 
are  erected  for  striking.  Each  fang  is  connected  with  the  duct  of  a 


FIG.  102. — Head  of  rattlesnake, 
dissected  to  show  the  oval  poison 
gland  behind  and  below  the  eye,  and 
the  curved  duct  connecting  gland 
with  fang.  "Pit"  is  between  eye 
and  nostril. 


REPTILIA 


155 


poison  gland,  the  latter  lying  in  the  side  of  the  head  behind  the  eye, 
Fig.  102. 

The  fangs  are  shed  at  intervals  of  about  three  months,  and  it  is 
not  very  unusual  to  see  two  fangs  on  one  side  of  the  jaw;  the  skull  of 
one  of  these  vipers  will  show  a  series  of  fangs,  one  behind  the  other, 
Fig.  103,  ready  to  replace  the  functional  ones  when  lost.  It  is  evident, 


PIG.  103. — Skull  of  a  pit  viper,  showing  functional  and  developing  fangs. 
Also  disarticulated  symphysis  of  lower  jaw.  Enlarged.  (From  Dilmars,  The 
Reptile  Book. 

then,  that  removal  of  the  fangs  of  these  serpents  renders  them  only 
temporarily  innocuous,  perhaps  not  even  temporarily  so,  as  poison 
would  probably  enter  the  wounds  caused  by  the  ordinary  small  teeth 
of  the  snake. 

The  effect  upon  the  human  system  of  the  bite  of  our  pit  vipers 
depends  upon  several  conditions:  the  size  of  the  snake,  the  location  of 
the  wound,  and  the  promptness  and  character  of  the  treatment. 


156  ECONOMIC   ZOOLOGY 

The  copperhead,  which  is  the  smallest  representative  of  the  three 
groups  of  pit  vipers,  except  some  of  the  smallest  rattlers,  perhaps  never 
proves  fatal  to  a  human  adult,  at  any  rate  the  author  has  never  heard 
nor  read  of  a  fatal  case,  though  he  has  met  several  persons  who  had 
been  bitten  by  this  species  of  snake. 

The  moccasin,  to  be  described  later,  though  belonging  to  the  same 
genus  as  the  copperhead,  reaches  a  much  larger  size,  and  may  inflict  a 
fatal  wound. 

The  bite  of  one  of  the  larger  rattlers  may  cause  the  death  of  a  man 
within  an  hour's  time,  while  some  of  the  "ground"  or  pigmy  rattlers  are 
so  small  that  their  bite  would  probably  not  be  a  very  serious"  matter 
to  a  healthy  man. 

To  illustrate  the  virulence  of  rattlesnake  venom  the  author  put  a 
mouse  in  the  cage  with  a  young  Timber  Rattler  scarcely  more  than  a 
foot  long.  With  a  single,  lightning-like  stroke  the  rattler  hit  the  mouse, 
which  dropped  in  its  tracks  and,  with  a  convulsive  quiver,  was  dead  in 
less  than  15  seconds.  Other  mice,  when  struck  by  the  same  snake, 
lived  for  a  much  longer  time,  probably  not  having  been  struck  in  so 
vital  a  spot. 

Although  so  deadly,  there  are  extremely  few  deaths  in  this  country 
from  the  bite  of  rattlesnakes  and  other  venomous  serpents;  this  is  in 
marked  contrast  to  some  of  the  tropical  countries;  in  India,  for  example, 
more  than  20,000  people  are  killed  each  year  by  poisonous  snakes. 
This  high  mortality  is  doubtless  due  not  only  to  the  great  abun- 
dance of  snakes,  but  also  to  the  fact  that  a  large  proportion  of 
the  dense  population  goes  about  with  bare  feet  and  legs,  thus  giving  the 
short-fanged  serpents  of  that  region  every  opportunity  to  get  in  their 
deadly  work.  The  fangs  of  even  some  of  the  large  cobras  of  the  orient 
are  so  short  that,  it  is  said,  they  cannot  reach  the  flesh  through  ordi- 
nary clothing,  so  that  Europeans  living  in  these  cobra-infested  regions 
are  not  often  injured. 

Records  of  serious  or  even  fatal  accidents  with  rattlesnakes  in 
captivity  are  fairly  numerous. 

As  to  the  best  treatment  of  injuries  from  venomous  snakes  authori- 
ties differ  somewhat,  though  the  general  treatment  that  is  recommended 
is  about  as  follows,  promptness  being  of  prime  importance:  if  the 
wound  be  upon  the  arm  or  leg,  and  it  nearly  always  is,  immediately  put  a 
tight  ligature  (a  handkerchief  twisted  with  a  stick,  if  nothing  better  be 


REPTILIA  157 

at  hand)  above  the  wound  to  stop,  as  far  as  possible,  the  circulation;  this 
ligature  should  not  be  left  on  more  than  half  an  hour  as  gangrene  may 
set  in  otherwise;  after  applying  the  ligature  cut  open  the  wound  with  a 
sharp  knife  to  cause  free  bleeding;  some  authorities  say  to  suck  the  blood 
from  the  wound  with  the  lips,  others  say  this  does  the  patient  no  good 
and  may  poison  the  person  who  does  the  sucking  if  he  happen  to  have 
any  sores  in  his  mouth.  The  wound  should  now  be  thoroughly  washed 
with  a  strong  solution  of  potassium  permanganate  in  water,  or, 
better,  the  solution  should  be  injected  into  the  wound  with  an  hypo- 
dermic syringe;  in  the  meantime,  a  physician  should  be  got  as  soon 
as  possible. 

The  old  idea  that  intoxicating  doses  of  alcohol  are  of  use  in  such  cases 
is  no  longer  held;  the  patient  may  recover  in  spite  of  such  treatment, 
not  because  of  it.  Slight  doses  of  alcohol  may  sometimes  be  useful  as 
a  stimulant,  and  in  some  cases  hypodermic  injections  of  strychnia  may 
be  necessary.  Tincture  of  iodine  is  recommended  by  some  for  washing 
out  this  wound,  but  the  potassium  permanganate  solution  seems  to  be 
the  accepted  and  easily  obtainable  antidote  for  the  poison. 

It  should  be  remembered  that  a  snake  wound  is  unusually  suscep- 
tible to  blood  poisoning,  so  that  it  should  be  kept  carefully  washed  and 
covered  with  aseptic  solutions  and  cloths.  Animals  killed  by  snake 
venom  decompose  rapidly  because  of  the  decrease  in  bactericidal  power 
of  the  blood  caused  by  the  venom. 

Venoms  of  various  snakes  vary  greatly  in  their  toxic  properties,  the 
most  important  types  being:  (i)  those  which  attack  the  nervous  system; 
(2)  those  which  attack  the  blood  corpuscles;  (3)  and  those  which  cause 
hemorrhages  by  attacking  the  endothelium  of  blood  vessels. 

Antivenom  sera  are  now  on  the  market  that,  when  injected  hypoder- 
mically  into  some  part  of  the  body  where  they  will  quickly  get  into  the 
circulation,  produce  good  results  in  combating  the  venom.  Their 
use  is  strongly  advocated  by  some  authorities;  but,  to  be  effective,  they 
must  be  injected  within  a  few  hours  after  the  bite  has  occurred.  Ac- 
cording to  Ricketts  and  Dick  the  antivenin  of  Calmette  is  not  effective 
against  all  snake  venom  as  was  formerly  claimed. 

It  is  certainly  well  for  those  who  travel  in  some  sections  of  the  coun- 
try, where  the  larger  rattlers  or  moccasins  abound,  to  carry  a  small 
case  containing  some  crystals  of  potassium  permanganate,  an  hypoder- 
mic syringe,  a  rubber  ligature,  some  gauze,  some  disinfectant,  and  a 


158 


ECONOMIC   ZOOLOGY 


REPTILIA  159 

very  sharp  scalpel.  Heavy  leggins  will,  of  course,  greatly  diminish 
the  danger  of  being  bitten. 

The  Water  Moccasin  or  "Cotton-mouth"  Ancistrodon  piscivorus, 
Fig.  104.  Since  this  reptile  is  confined  to  the  South  Atlantic  and  Gulf 
States  and  the  lower  Mississippi  valley  it  is  of  no  direct  interest  to  a 
large  portion  of  the  country.  It  is  a  thick-bodied  snake  that  may  reach 
a  length  of  4  or  5  feet.  The  characteristic  markings  seen  in  young 
animals  may  disappear  with  age,  so  that  it  may  not  be  easy,  at  first,  to 
recognize  this  species;  but  if  the  pit  and  elliptical  pupil  be  there,  beware! 
In  its  native  haunts  this  snake  is  active  and  rather  aggressive,  and  is 
very  justly  dreaded,  as  the  bite  of  a  large  cotton-mouth  may  prove 
fatal.  It  is  usually  found  in  swamps  and  along  sluggish  streams,  hang- 
ing on  bushes  or  lying  on  half  sunken  logs.  Its  popular  name  is 
doubtless  derived  from  the  white  mouth-parts  exhibited  by  the  snake 
as  it  opens  its  mouth  before  striking. 

There  are  several  water  snakes  that  are  popularly  called  "  moccasins' ' 
and  are  commonly  supposed  to  be  venomous,  but  they  are  quite  harm- 
less, in  spite  of  their  willingness  to  bite;  they,  of  course,  do  not  possess 
the  pit  nor  the  elliptical  pupil,  nor  do  they  reach  the  large  dimensions 
of  the  cotton-mouth.  The  writer  has  been  bitten  by  these  so-called 
"  moccasins  "  without  the  slightest  ill  effects.  Because  of  the  character 
of  its  habitat  there  are  probably  few  serious  accidents  caused  by  the 
"cotton-mouth"  but  it  would  be  well  for  those  living  within  its  range 
to  become  familiar  with  its  appearance. 

The  Copperhead  Snake,  Highland  Moccasin,  etc.,  Ancistrodon 
contortrix,  Fig.  105.  This  snake,  which  is  pretty  generally  distributed 
over  the  eastern  and  southern  part  of  the  United  States,  is,  as  the  name 
shows,  a  close  relative  of  the  preceding.  It  is  somewhat  variable,  but 
usually  shows  more  distinct  markings  than  the  moccasin — chestnut 
bands  across  a  lighter  ground  color.  The  name  comes  from  the  distinct 
coppery  color  of  the  top  of  the  head.  It  is  not  so  large  a  snake  as  the 
preceding,  seldom,  if  ever,  reaching  a  length  of  4  feet;  most  of  the 
specimens  seen  by  the  author  have  been  under  3  feet.  It  inhabits 
dry,  rocky  regions,  rather  than  swamps,  hence  one  of  its  popular  names 
"  Highland  Moccasin. "  It  is  also  frequently  found  in  cultivated  fields. 
There  are  several  perfectly  harmless  snakes,  to  be  noted  below,  that  are 
frequently  mistaken  for  the  copperhead,  but  the  pit  and  elliptical  pupil 
will  distinguish  the  latter. 


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161 


While  a  properly  directed  bite  of  a  large  copperhead  might  prove 
fatal,  the  author,  as  noted  above,  has  never  heard  an  authentic  report 
of  a  death  from  the  bite  of  this  species. 

In  many  thickly  settled  parts  of  the  country  the  copperhead  has 
been  practically  exterminated,  but  in  other  regions  it  is  uncomfortably 
abundant. 


PIG.   106. — Diamond  rattler,  Crotalus  adamantous,  caught  alive  in  Florida. 

The  Rattlesnakes,  genera  Crotalus  and  Sistmrus,  Fig.  106.  Little 
need  be  said  of  these  most  famous  of  our  American  serpents.  It  is 
unnecessary  here  to  look  for  the  pit  nor  for  the  elliptical  pupil,  since 
that  curious  structure,  the  rattle,  is  always  to  be  found  at  the  end 
of  the  tail;  and  he  who  has  once  heard  that  ominous  sound  is  not  apt 
11 


1 62  ECONOMIC   ZOOLOGY 

to  forget  it.  Like  the  copperhead,  the  rattlers  have  been  practically 
exterminated  in  many  thickly  settled  places,  but  there  are  few  regions 
of  any  extent  in  the  country  where  at  least  one  species  may  not  be 
found. 

Something  over  a  dozen  species  are  recognized  in  the  United  States, 
nearly  all  of  them  falling  under  the  genus  Crotalus. 

They  vary  in  size  from  the  terrible  Diamond-back  C.  adamanteus, 
Fig.  1 06,  of  the  southeastern  part  of  the  United  States,  one  of  the  most 
deadly  of  all  serpents,  which  may  reach  a  length  of  8  feet  and  a  diame- 
ter of  4  or  more  inches,  to  the  Pigmy  or  Ground  Rattler  of  Florida, 
Sistrurus  miliarius,  adult  specimens  of  which  may  be  less  than  18 
inches  long;  the  difference  in  the  effects  of  the  bites  of  these  two 
species  is  correspondingly  great. 

Since  the  rattler  usually  sheds  its  skin  three  times  a  year,  and  since 
a  new  segment  is  added  to  the  rattle  at  each  shedding,  by  allowing  the 
"button"  and  first  ring  for  the  first  year,  the  age  of  the  snake  may  be 
calculated  by  the  number  of  segments  in  the  rattle,  provided  some  of  the 
segments,  as  is  often  the  case,  have  not  been  lost. 

The   treatment   of   rattlesnake-bite  has   been   dealt  with  above. 

It  will  be  seen,  then,  that  it  is  a  comparatively  simple  matter  for 
anyone  to  learn  to  recognize  the  venomous  serpents  of  his  locality,  and 
such  information  may,  at  some  time,  be  of  vital  importance  to  its 
possessor. 

Let  us  now  turn  to  that  much  larger  group,  the  non- venomous  snakes, 
a  number  of  which  will  be  mentioned  briefly.  Many  will  not  be  men- 
tioned, either  because  their  economic  value  is  debatable  or  because  of 
lack  of  information  in  regard  to  their  habits. 

The  Garter  Snakes.  Genus  Eutania. — The  Striped  Snakes  are  the 
most  abundant  of  North  American  serpents,  and  are  found  over 
the  entire  continent,  wherever  snakes  are  found.  The  numerous 
species  are  extremely  variable,  but  most  people  that  know  anything 
about  snakes  recognize  the  garter  or  ribbon  snakes  of  their  region. 
They  are  usually  small,  2  feet  or  less  in  length,  and  most  of  them  have 
one  or  more  longitudinal  stripes.  They  all  produce  their  young  alive 
and  in  large  numbers.  Since  they  feed  entirely  upon  cold-blooded 
animals,  frogs,  toads,  fish,  etc.,  they  are  not  only  not  useful  to  the  farmer, 
but  should  be  considered  of  some  negative  importance  as  destroyers  of 
useful  animals,  though,  possibly,  the  very  young  snakes  may  be  of  use 


REPTILIA 


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164  ECONOMIC  ZOOLOGY 

as  destroyers  of  insects  or  insect  larvas;  at  least  they  are  entirely 
non-venomous. 

The  Water  Snakes.  Genus  Tropidonotus,  Fig.  107.  Under  this 
genus  are  several  dozen  species  of  semi-aquatic  snakes,  many  of  which 
are  well  known.  Since,  like  the  garter  snakes,  their  food  consists 
of  frogs,  toads,  fish  and  other  cold-blooded  animals,  they  are  probably 
of  no  benefit  to  man,  and  may  do  .some  harm  in  destroying  useful 
animals.  Many  of  them  are  of  ugly  disposition  and  will  strike  with 
sufficient  force  to  bring  blood,  but  they  are  all  entirely  non- venomous. 
Among  the  better  known  forms  under  this  genus  are  the  Common 
Water  Snake,  T.fasciatus,  sipedon,  found  from  Maine  to  North  Carolina 
and  west  to  Kansas;  the  Banded  Water  Snake  or  Moccasin,  T.  fasciaius, 
which  extends  from  Virginia  south;  and  the  Brown  Water  Snake  or 
Water  Rattle,  T.  taxispilotus,  the  largest  of  American  Water  Snakes, 
reaching  a  length  of  5  feet  and  with  a  thick  body,  found  in  the 
States  south  of  the  Potomac  and  east  of  the  Mississippi. 

One  of  the  chief  points  of  interest  in  connection  with  these  Water 
Snakes  is  the  fact  that  they  are  so  frequently  confused  with  the  deadly 
"Cotton-mouth"  Moccasin,  or,  if  recognized  as  distinct,  they  are 
thought  to  be  venomous  themselves.  The  Banded  Water  Snake, 
in  particular,  with  its  thick  body  and  flat,  distinct  head,  is  easily 
mistaken  for  the  venomous  species,  but  the  pit  and  the  elliptical 
pupil  will  distinguish  the  latter  unfailingly. 

The  Brown  or  Ground  Snakes. — This  group  of  small  snakes, 
measuring  from  8  to  14  inches  in  length,  is  represented  by  several 
genera,  most  of  which  are  of  retiring,  even  subterranean  habits. 
They  are  of  a  dull  brown  color  above,  with  few,  if  any  markings; 
the  ventral  side  is  white,  yellow,  pink,  or  vermilion,  depending  upon  the 
species.  Since  their  food  consists  of  insects,  insect  larvae,  slugs,  etc., 
they  may  be  considered  highly  beneficial,  and  their  diminutive  size 
and  gentle  habits  leave  not  the  least  excuse  for  their  destruction. 
They  are  distributed  over  practically  the  entire  United  States  and 
southern  Canada  east  of  the  Rockies. 

The  Racers.  Genera  Spilotes  and  Zamenis. — Several  well-known 
and  useful  serpents  are  found  in  this  group.  Under  the  first  genus 
is  found  the  Gopher,  Indigo  or  Rat  Snake,  S.  corais  couperi,  a  large 
snake  with  shiny  black  scales,  both  above  and  below,  but  with  reddish 
chin  and  throat.  It  may  reach  a  length  of  8  feet  or  more.  It 


REPTILIA 


165 


1 66  ECONOMIC  ZOOLOGY 

is  found  in  the  South  Atlantic  and  Gulf  States,  where  its  value  as  a 
ratter  is  often  recognized;  it  is  encouraged  to  live  about  barns  and  out- 
houses and  is  regarded  almost  as  a  pet. 

The  Blacksnake  or  Black  Racer,  Z.  Constrictor,  Fig.  108,  is  a  dull 
rather  than  a  glossy  black,  has  a  white  instead  of  a  reddish  throat, 
and  has  smooth  not  keeled  scales.  It  is  fairly  slender  and  may  reach 
a  length  of  7  feet,  possibly  more.  It  is  not  a  constrictor.  According  to 
Nelson  "They  frequently  pursue  people  when  they  retreat,  but  retreat 
themselves  when  the  person  pursues  them."  It  is  abundant  east  of  the 
Mississippi;  further  west  it  is  replaced  by  the  Blue  Racer,  variety 
flamventriSj  with  similar  habits.  This  species  is  of  great  value  to 
agriculture  as  a  destroyer  of  destructive  rodents,  but  in  spite  of  this 
it  is  very  generally  killed  by  farmers  and  others  just  "because  it  is  a 
snake." 

The  Rat  Snakes.  Genus  Coluber. — These  so-called  Rat  or  Chicken 
Snakes  are  usually  large,  and  since  they  feed  on  warm-blooded  animals 
most  of  them  are  of  value  to  man  as  destroyers  of  rodents,  though 
some  destruction  of  birds  is  caused  by  some  species. 

The  Fox  Snake  or  Red-headed  Coluber,  C.  vulpinus,  named  from 
the  fox-like  odor  of  newly  captured  specimens,  is  a  fairly  large,  brownish, 
spotted  snake  found  throughout  the  Central  States,  where  it  is  of 
distinct  value  to  agriculture  as  a  destroyer  of  rodents;  since  it  often 
seeks  its  prey  in  the  vicinity  of  barns  it  is  sometimes  called  the  House 
Snake. 

Emory's  Coluber  or  Spotted  Chicken  Snake,  C.  emoryi,  is  another 
useful  Coluber  found  in  the  states  west  of  the  Mississippi,  from  Kansas 
south. 

The  Red  Coluber,  C.  guttatus,  called  variously  the  Corn,  Red 
Chicken,  Mouse,  or  House  Snake,  is  a  fairly  large  snake  inhabiting 
the  states  south  of  Pennsylvania  and  east  of  the  Mississippi.  Its 
pale  red  back,  with  crimson  saddles,  and  its  white  belly  with  large 
black  squares,  make  it  easy  to  recognize.  It  is  useful  as  a  destroyer 
of  rodents. 

The  Black  Coluber  or  Pilot  Blacksnake.  C.  obsoletus. — This,  snake 
may  reach  a  length  of  8  feet  or  over  and  is  frequently  confused 
with  the  Common  Blacksnake  or  Racer,  from  which  it  may  be  distin- 
guished by  its  keeled  and  polished  scales.  It  is  found  practically  all 
over  the  states  east  of  the  Mississippi  and  into  Texas,  and  is  a  useful 


REPTlLIA  167 

rodent  destroyer,  though  it  does  some  damage  to  poultry  and  wild 
birds. 

The  Four-banded  Coluber,  Banded  or  Yellow  Chicken  Snake.  C. 
obsoletus  quadrimttatus. — This  snake  is  found  in  the  states  from  North 
Carolina  south,  and  west  to  the  Mississippi.  It  is  sometimes  found  on 
the  rafters  of  barns  and  chicken  houses  where  it  feeds  not  only  upon  rats 
and  mice  but  also  upon  eggs  and  young  chickens.  Whether  the  harm  it 
does  in  destroying  poultry  is  more  than  balanced  by  the  good  it  does 
in  destroying  rodents  is  hard  to  determine. 

The  Bull  Snakes.  Genus  Pituophis,  Fig.  109.  The  three  species 
of  this  genus,  found  in  various  parts  of  the  country,  are  useful  since 
they  feed  largely  upon  destructive  mammals. 

The  Green  Snakes.  Cyclophis  astivus  and  Liopeltis  vernalis. — These 
small  snakes  are  easily  recognized  by  their  uniform  green  color 
above;  the  former,  the  Keel-scaled  Green  Snake,  is  the  larger,  has 
keeled  scales,  as  the  name  indicates,  and  is  yellowish  beneath;  the 
latter,  the  Green  or  Grass  Snake,  is  whitish  beneath,  has  smooth  scales, 
and  is  rarely  over  20  inches  long.  They  are  very  gentle  snakes  and 
are  useful  as  destroyers  of  insects. 

The  King  Snakes.  Genus  Ophibolus. — This  group  includes  some  of 
our  well-known  snakes,  harmless  to  man,  but  often  destructive  to 
venomous  and  other  snakes;  hence  their  popular  name.  They  are 
useful  to  man  not  only  as  destroyers  of  dangerous  serpents  but  as 
destroyers  of  mammalian  pests. 

But  two  representatives  of  this  group  can  be  mentioned  here;  the 
Common  King  Snake,  Chain  Snake,  or  Thunder  Snake,  O.  getulus, 
and  the  Milk  or  House  Snake  or  Spotted  Adder,  O.  doliatus  triangulus. 

The  Common  King  Snake,  Fig.  no,  is  a  variable  species  that  is 
found  generally  over  the  United  States  south  of  latitude  40°.  It  may 
reach  a  length  of  5  feet  or  more,  and  is  usually  black  or  dark,  with 
narrow  whitish  or  yellowish  lines  across  the  back  in  a  pattern  some- 
what like  the  links  of  a  chain,  hence  one  of  its  popular  names.  This 
snake,  so  gentle  toward  man,  not  only  destroys  other  snakes,  but  seems 
quite  immune  to  the  venom  of  the  deadly  serpents. 

The  Milk  Snake  is  also  variable  and  widely  distributed,  and  is  named 
from  the  supposed  habit  it  has  of  sucking  milk  from  cows;  this  snake 
does  not  steal  milk,  but  is  quite  useful  as  a  destroyer  of  rodents,  espe- 


i68 


ECONOMIC  ZOOLOGY 


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169 


0-3 


170  ECONOMIC  ZOOLOGY 

daily  about  barns  and  houses  which  it  may  frequent;  from  this  habit 
it  gets  the  name  of  House  Snake. 

The  Hog-nosed  Snakes.  Genus  Heterodon. — Practically  the  entire 
United  States  is  inhabited  by  one  or  other  of  the  three  species  of  Hog- 
nosed  Snakes.  They  are  blotched  or  black  snakes  with  rather  thick 
bodies  and  strangely  upturned  snouts  that  give  the  popular  name. 
They  have  the  flat,  distinct  head  that  is  supposed  to  be  characteristic 
of  venomous  serpents,  and  this,  with  the  habit  they  have  of  swelling 
up  the  body  with  air  and  then  blowing  it  out  with  a  hissing  sound, 
has  caused  them  to  be  almost  universally  considered  venomous, 
though  they  are  entirely  harmless  to  man.  This  curious  habit  has 
given  the  popular  name  of  Puff  Adder  or  Blowing  Viper.  Their 
tendency  to  live  in  dry  places  has  doubtless  given  rise  to  the  name  Sand 
Viper.  Since  these  snakes  are  said  to  feed  chiefly  upon  toads  and  frogs 
they  cannot  be  said  to  be  beneficial  to  man,  but  rather  the  reverse. 

Among  some  savage  and  even  civilized  peoples  the  boas  and  other 
large  snakes  are  often  used  for  food.  The  meat  is  firm  and  white,  and 
is  said  to  taste  somewhat  like  veal.  Snake  eggs  also  are  used  for  food, 
it  is  said. 

Snake  "wine"  is  sold  in  China,  and  in  this  country  rattlesnake  oil  is 
sold  as  a  medicine,  which,  it  is  claimed,  is  good  for  various  aches  and 
pains,  though  its  medicinal  value  is  probably  no  greater  than  that  of 
any  common  animal  oil. 

Crocodilia. — More  than  100  years  ago  attempts  were  made  to 
utilize  the  skin  of  the  alligator,  but  it  was  not  until  about  1855  that 
these  attempts  were  successful  and  alligator  leather  became  somewhat 
fashionable  and  some  thousands  of  hides  were  converted  into  leather. 
The  demand  was  short-lived,  however,  and  was  not  again  felt  until  the 
demand  for  shoe-leather  during  the  war  between  the  States  revived  the 
business.  At  the  close  of  the  war  the  business  again  failed,  but  about 
1869  the  demand  became  greater  than  ever  and  has  continued  unabated 
almost  to  tKe  present  time.  The  supply  of  skins  from  our  own  States 
proving  inadequate,  large  numbers  of  skins  were  soon  imported  from 
Mexico  and  Central  America.  The  skins  from  South  America  are  so 
heavy  that  they  are  of  little  value  in  making  leather.  Of  the  States  of 
the  Union,  Florida  has  been  the  chief  producer,  the  most  important 
centres  for  hides  being  Cocoa,  Melbourne,  Fort  Pierce,  Miami,  and 
Kissimmee.  Ten  men  at  the  first-named  place  took,  in  1899-1900, 


REPTILTA  171 

2500  skins;  one  man  took  800  skins  in  i  year;  another  man  collected 
42  skins  in  one  night.  At  Fort  Pierce  12  men  took  4000  skins  in 
1889.  In  1899,  three  firms  at  Kissimmee  handled  33,600  hides.  After 
this  time  the  total  number  of  hides  taken  and  the  average  per  man 
diminished  greatly. 

Besides  being  killed  for  their  hides,  the  alligators  have  been  de- 
stroyed by  the  thousands  merely  for  wanton  sport,  so  that  in  1902  it 
was  estimated  their  numbers  in  Florida  and  Louisiana  were  less  than 
one-fifth  of  what  they  were  20  years  before  that  time,  and  unless  steps 
be  taken  to  prevent  it,  the  alligator  hide,  as  an  article  of  commerce,  may 
cease  to  exist  in  our  Southern  States. 

It  has  been  claimed  that  the  destruction  of  the  alligator  has  allowed 
the  cane  rat  and  muskrat  to  increase  to  a  serious  extent,  the  former 
doing  great  damage  to  crops,  the  latter  often  injuring  the  levees  to  a 
dangerous  extent.  Legislation  to  forbid  the  killing  of  alligators  of  less 
than  4  or  5  feet  in  length  has  been  suggested  and  should  be  passed, 
since  animals  of  less  size  have  almost  no  commercial  value  for  leather. 

In  1902,  the  annual  output  from  the  tanneries  of  the  United  States 
approximated  280,000  skins,  worth  about  $420,000.  Of  these  about 
56  per  cent,  came  from  Mexico  and  Central  America,  22  per 
cent,  from  Florida,  20  per  cent,  from  the  other  Gulf  States. 
South  American  hides  are  not  handled  by  the  United  States  markets. 

Probably  the  greater  part  of  the  hides  from  Mexico  and  Central 
America  are  those  of  the  Caiman. 

In  1908,  there  were  marketed  from  the  South  Atlantic  and  Gulf 
States  372,000  pounds  of  alligator  hides,  valued  at  $61,000. 

According  to  the  United  States  Bureau  of  Fisheries  the  hunter 
in  1891  averaged  about  60  cents  for  the  skin,  while  in  1902  the  price 
averaged  about  90  cents,  varying  between  15  cents  and  $2,  depend- 
ing on  the  size  and  condition  of  the  skin.  "Prime  hides  5  feet  long, 
with  no  cuts,  scale  slips,  or  other  defects,  are  worth  about  95  cents  each, 
in  trade,  when  the  hunter  sells  them  at  the  country  stores,  and  about 
$1.10  cash,  at  the  tanneries.  Those  measuring  7  feet  are  worth  $1.55; 
6  feet,  $1.12;  4  feet,  52  cents,  and  3  feet,  25  cents.  Little  de- 
mand exists  for  those  under  3  feet  in  length"  (Report  of  Commis- 
sioner of  Fish  and  Fisheries,  1902,  p.  345).  Hides  of  7  feet  are  in 
most  demand,  those  over  10  feet  are  not  much  used.  The  income 


172  ECONOMIC   ZOOLOGY 

of  the  hunters  is  largely  increased  by  the  sale  of  otter,  bear,  deer,  and 
other  skins. 

"The  skin  should  be  removed  soon  after  death  as,  in  warm  climates,  pu- 
trefaction sets  in  very  early  and  the  value  of  the  skin  is  depreciated.  After 
removal,  the  flesh  side  of  the  skin  is  thoroughly  rubbed  with  fine  salt,  and  the 
skin  is  carefully  rolled  up  with  the  salted  side  inside  and  is  ready  for  shipment, 
but  must  be  kept  in  a  dry,  cool  place.  Great  care  must  be  taken  not  to  cut 
the  hide  since  small  cuts  that  are  not  noticeable  in  the  raw  skin  may  be  so 
conspicuous  in  the  dressed  skin  as  to  render  it  of  much  less  value;  a  large  per- 
centage of  the  hides  received  in  the  markets  are  thus  damaged. 

"Formerly  only  the  'belly  skin'  was  removed,  by  two  longitudinal  in- 
cisions just  below  the  horny  portion  of  the  back;  but  it  was  later  found 
that  the  thick  horny  skin  of  the  back  could  be  tanned  nearly  as  well  as  the 
thinner  belly  skin,  so  that  the  entire  skin  is  now  usually  removed  by  a  longi- 
tudinal incision  along  the  mid- ventral  line,  with  lateral  incisions  along  each 
leg  to  the  foot.  The  entire  skin  is  more  commonly  taken  in  Mexico  and 
Central  America  than  in  our  States,  Fig.  in. 

"Although  the  raw  skins  are  sold  according  to  length,  the  tanned  hides 
are  sold  by  the  width  of  the  leather  at  the  widest  part.  Standard  hides 
sell  for  $i.oo  to  $1.65  per  12  inches  of  width.  Some  skins  tanned  and 
dyed  in  a  superior  manner  sell  for  $2  or  more  for  single  skins  of  2^ 
feet  in  length.  As  a  rule  the  Louisiana  skins  fetch  the  highest  prices, 
and  those  from  Florida  the  lowest.  Imitation  alligator  leather  is  now 
prepared  in  large  quantities,  principally  from  sheepskins  or  the  buffing  from 
cowhides.  These  are  tanned  according  to  the  usual  process,  and  before  the 
skins  are  finished  they  are  embossed  with  the  characteristic  alligator  markings 
by  passing  them  between  two  rollers."  (Above-mentioned  report,  p.  346.) 

Very  little  of  the  leather  is  now  used  in  making  shoes,  the  chief 
demand  being  for  handbags,  music-rolls,  etc.  In  fact  at  the  present 
time  (1919)  alligator  leather  is  so  little  in  vogue  that  the  business  is 
said  to  be  nearly  dead. 

In  hunting  alligators  for  their  hides  two  methods  are  usually  em- 
ployed, in  the  Southern  States  at  least.  The  common  method  is 
"fire-hunting"  at  night;  the  hunters  go,  either  singly  or  in  pairs, 
usually  in  boats,  sometimes  on  foot,  with  shotgun  and  torch.  The  torch 
may  be  fastened  to  the  hunter's  hat,  after  the  manner  of  the  miner's 
lamp.  A  more  progressive  hunter,  employed  by  the  writer  had,  as 
a  torch,  an  acetylene  lamp,  attached  to  his  hat,  with  the  tube  for  the 
gas  extending  down  his  back  to  the  generator  in  his  pocket.  This  lamp 


REPTILIA 


FIG.  in. — Skins  of  alligator.     "Belly"  skin  on  left;  whole  skin  on  right.     (From 
Stevenson,  Utilization  of  the  Skins  of  Aquatic  Animals,  in  Report  of  U.S.F.C.  1902.) 


\ 

174  ECONOMIC   ZOOLOGY 

threw  a  blinding  beam  of  light  far  across  the  swamp  into  the  eyes  of  the 
unsuspecting  'gator,  which  usually  remained  fascinated  until  it  could 
be  approached  to  within  easy  range.  A  shotgun  at  close  range,  of 
course,  blows  off  nearly  the  entire  top  of  the  animal's  head  and  kills 
it  instantly;  it  is  then  seized  before  it  sinks  out  of  reach  and  is  either 
taken  into  the  boat  or  dragged  upon  the  bank  to  be  collected  with  others 
in  the  early  morning. 

In  daylight,  with  no  glaring  light  to  hypnotize  it,  the  alligator  is 
difficult  to  approach  within  range  and  it  usually  disappears  into  its 
cave  before  the  hunter  can  get  a  shot  at  it.  The  daylight  hunter, 
then,  should  be  supplied  not,  of  course,  with  a  light,  but  with  a  10- 
or  1 5-foot  pole  with  a  large  iron  hook  at  the  end.  If  the  alligator 
be  vigorously  prodded  with  this  mammoth  fish-hook  he  will  usually 
finally  seize  it  with  his  mouth  and  can  be  pulled  out  of  his  hole  alive. 
It  is  then  an  easy  matter  to  kill  him  with  a  bullet  through  the  base  of  the 
brain.  I  have  seen  an  8-foot  alligator  thus  killed  with  a  little  .22 
calibre  "cat"  rifle.  An  8-foot  alligator  will  often  be  all  that  two 
men  can  manage  to  drag  out  of  his  cave  in  this  way;  and,  in  the  torrid 
heat  of  the  southern  swamp,  this  violent  exercise  is  not  to  the  liking 
of  the  usually  not  very  energetic  hunter. 

While  the  manufacture  of  leather  gives  or  gave  the  chief  value  to  the 
alligator  there  are  other  ways  in  which  it  has  some  economic  importance. 
Chief  of  these  is  probably  the  sale  of  alligator  goods  to  tourists.  In 
1891  there  were  in  Jacksonville,  Florida,  twelve  dealers  in  live  and 
stuffed  alligators.  In  1 890, 8400  alligators  were  sold  to  tourists,  the  price 
for  the  live  animals  varying  from  $10  to  $35  per  hundred.  For  in- 
dividual animals  of  the  smallest  size  (less  than  12  inches  long) 
the  price  is  usually  from  50  cents  to  $i.  For  a  3-foot  alligator 
the  price  is  generally  $3  to  $5;  for  sizes  over  3  feet  $2  per  foot 
may  be  charged,  though  for  very  large  specimens  the  price  may  be 
from  $50  to  $300  each. 

Besi'des  the  live  and  stuffed  animals,  the  teeth  are  polished  and  sold 
as  souvenirs;  about  450  pounds  of  teeth  were  sold  in  1890,  at  a  price 
varying  from  $i  to  $2  per  pound.  From  75  to  200  teeth  will 
make  a  pound. 

In  1891  about  forty  people,  in  addition  to  the  regular  dealers,  were 
engaged,  in  the  United  States,  in  stuffing  alligators,  polishing  teeth,  etc. 
The  teeth  are  extracted  by  burying  the  head  until  decomposition  sets  in. 


REPTILIA  175 

The  tiny  alligators  that  are  most  commonly  sold  to  tourists,  to  be 
brought  North,  perhaps,  and  allowed  to  freeze  or  starve  to  death,  may 
either  be  caught  by  a  wire  noose  at  the  end  of  a  fishing  rod,  or  they 
may  be  hatched  from  eggs  that  are  taken  from  the  nests  shortly  before 
they  are  ready  to  hatch.  Such  eggs  may  readily  be  hatched  by  simply 
keeping  them  moist  and  at  a  fairly  constant  temperature.  Besides  the 
above  uses  Ditmars  says: 

"The  eggs  are  eaten  in  many  portions  of  the  South,  and  the  search  for 
eggs  at  the  proper  season  furnishes  profitable  employment  for  many  persons, 
as  each  nest  contains  a  large  number  of  eggs,  about  30  in  the  average  nest." 

Never  having  eaten  an  alligator  egg  I  cannot  speak  from  personal 
experience  of  its  flavor;  but  it  has  always  seemed  strange  to  me  that 
more  use  is  not  made  of  the  flesh  of  the  alligator.  This  flesh  is  often 
said  to  have  too  strong  a  flavor  to  be  palatable;  I  have  eaten  it,  and  it 
had  no  rank  taste  but  was  decidedly  agreeable,  being,  as  might  perhaps 
be  expected  of  so  amphibious  an  animal,  somewhat  like  both  fish  and 
flesh,  yet  not  exactly  like  either.  Perhaps  greater  care  should  be 
taken  in  skinning  an  animal  that  is  to  be  used  for  food  in  order  that  the 
flesh  be  not  tainted  with  the  musk.  It  may  be  a  lack  of  care  in  prepa- 
ration that  has  given  rise  to  the  impression  that  alligator  meat  is  too 
strong  to  be  pleasant.  It  is  perhaps,  also,  the  "idea"  of  eating  a 
reptile  that  makes  the  meat  unpopular.  A  half-grown  boy,  who  was 
once  in  the  swamps  with  me,  had  expressed  a  great  aversion  to  alligator 
meat,  so  the  guide,  one  day,  offered  him  a  nicely  fried  piece  of  alligator 
meat,  saying  it  was  fish;  the  meat  was  eaten  with  evident  relish  and  the 
diner  was  not  told  until  after  a  second  piece  had  disappeared  what  he 
had  been  eating.  It  always  seemed  strange  that  the  poor  people 
of  the  South  should  not  more  often  vary  the  monotony  of  fat  pork  and 
corn  bread  with  alligator  steaks.  Whether  the  meat  could  be  smoked, 
salted,  or  canned  so  that  it  would  keep  in  a  hot  climate  I  do  not  know; 
I  am  not  aware  of  any  experiments  along  this  line. 

An  article  by  the  writer  on  "Reptiles  as  Food,"  which  appeared 
in  the  December,  1917,  number  of  The  Scientific  Monthly,  having 
excited  the  curiosity  of  the  members  of  a  large  boarding  house  in 
Morgantown,  W.  Va.,  it  was  suggested  that  a  collection  be  taken  among 
those  interested  to  buy  a  couple  of  small  alligators  and  have  them 
cooked,  to  see  if  the  flesh  really  was  as  agreeable  as  was  claimed  in  the 


176  ECONOMIC  ZOOLOGY 

article  in  question.  The  writer  agreed  to  buy  the  animals  and  prepare 
the  flesh  for  cooking. 

Sufficient  funds  were  collected  to  buy,  of  the  Arkansas  Alligator 
Farm,  two  alligators,  each  about  three  feet  in  length.  These  were  killed 
by  cutting  the  cord  at  the  base  of  the  skull,  and  the  flesh  of  the  entire 
body  was  cut  into  pieces  of  suitable  size  for  cooking. 

The  meat  was  first  parboiled  (though  the  necessity  for  this  was 
doubtful)  and  was  then  fried  in  egg  and  cracker  crumbs,  very  much 
after  the  manner  of  a  breaded  veal  cutlet. 

About  thirty  people,  consisting  of  both  men  and  women,  mostly 
school  teachers,  members  of  the  university  faculty,  and  college  students, 
partook  of  the  repast,  and  all  declared  the  meat  to  be  "delicious." 

There  was  considerable  difference  of  opinion  as  to  what  the  meat 
resembled:  some  thought  it  tasted  like  pork;  some  thought  it  like  fish; 
one  person  said  it  suggested  lobster;  but  all  declared  it  to  be  most 
agreeable. 

Of  course,  at  the  prices  charged  by  supply  firms  the  cost  of  live 
alligators  would  be  prohibitive,  but  in  the  tropics,  where  crocodilia 
are  often  extremely  abundant,  the  flesh  could  be  had  at  a  very  low  cost. 

The  writer  has  seen  alligator  hunters,  in  our  southern  states,  throw 
hundreds  of  pounds  of  alligator  meat  to  the  carrion  crows  and  buzzards, 
after  removing  the  hides. 

Whether  the  Central  and  South  American  crocodiles  would  be  as 
pleasant  for  food  as  the  Florida  alligator  the  writer  can  not  say. 

While  the  Crocodilia  of  this  country  are  practically  harmless  to  man, 
there  are  one  or  two  species  found  elsewhere  of  which  this  cannot  by 
any  means  be  said.  The  African  Crocodile,  C.  niloticus,  for  example,  is 
said  to  destroy  more  human  lives  than  all  other  wild  animals  of  the 
Dark  Continent  combined;  and  the  Salt  Water  Crocodile,  C.  porosus, 
according  to  a  British  Blue-book,  caused  244  deaths  in  British  India 
in  the  year  1910.  The  black  caiman,  Caiman  niger,  of  South  America 
sometimes  attacks  small  domestic  animals  and  children;  even  grown 
people  may  at  times  be  attacked. 


CHAPTER  XIII 
AVES 

The  characteristics  of  this  familiar  class  are  more  definite  and  un- 
varying than  those  of  almost  any  other  class  in  the  animal  kingdom. 
Birds  are  known  by  their  feathers,  which  are  possessed  by  no  other  ani- 
mals. They  are  warm-blooded,  in  which  they  differ  from  all  preceding 
forms,  their  blood  being  several  degrees  warmer  than  that  of  man  and 
other  mammals. 

In  almost  all  living  species  the  anterior  appendages  are  developed  as 
wings  and  are  used  in  locomotion.  To  support  the  large  pectoral 
muscles  used  in  flight  the  sternum  is  usually  prolonged  into  a  ventrally 
projecting  keel  or  carina. 

In  all  living  birds  teeth  are  absent.  The  olfactory  organs  are  usu- 
ally poorly  developed  while  the  eye  is  unusually  large  and  perfect  and 
contains  a  pecten.  The  cervical  vertebrae  are  usually  numerous  while 
the  caudal  are  few  and  are  usually  fused  to  form  a  pygostyle  around 
which  the  tail  feathers  are  attached.  The  coracoid  is  usually  large  and 
pillar  like;  the  clavicles  are  united  to  form  the  familiar  "wish  bone;" 
and  the  scapula  is  long  and  sabre-shaped.  There  are  numerous  other 
internal  peculiarities  that  might  be  mentioned,  such  as  the  absence  of 
the  left  instead  of  the  right  (as  in  mammals)  aortic  arch  and  of  the  right 
ovary  and  oviduct;  the  frequent  enlargement  of  the  gullet  to  form  a 
crop  or  craw;  the  division  of  the  stomach,  in  some  forms,  into  the  glan- 
dular part  or  proventriculus  and  the  hard,  muscular  gizzard;  the  pres- 
ence of  air  spaces  in  the  bones  and  in  various  parts  of  the  body  that  are 
connected  with  the  lungs;  the  presence  of  a  peculiar  voice  apparatus, 
the  syrinx,  situated  at  or  near  the  point  of  division  of  the  trachea  into 
the  bronchi;  the  four-chambered  heart  containing  oval,  nucleated,  red- 
blood  corpuscles. 

Birds  are  all  oviparous;  the  egg  is  large  in  proportion  to  the  bird 
that  produces  it  and  consists  of  a  large  amount  of  yolk  and  albumen  in- 
closed in  a  hard,  calcareous  shell.  The  newly  hatched  young  are  either 

12  177 


178  ECONOMIC  ZOOLOGY 

covered  with  down  and  are  able  to  run  about  or  they  are  more  or  less 
naked,  blind  and  helpless;  in  the  former  case  they  are  said  to  be  pre- 
cocious, in  the  latter  case  they  are  called  non-precocious  or  altricial. 

Owing  to  their  common  occurrence  about  the  haunts  of  man  and 
to  their  attractive  appearance  and  songs  birds  have  been  more  generally 
studied  than  almost  any  other  class  of  animals.  Unfortunately,  however, 
owing  again  to  the  beauty  of  their  plumage  and  to  the  delicious  flavor 
of  their  flesh,  they  have  been  hunted  by  man  almost,  or  quite,  in  some 
cases,  to  the  point  of  extermination.  Of  recent  years,  fortunately, 
partly  through  the  efforts  of  the  Audubon  and  other  similar  societies, 
and  through  the  work  of  the  United  States  Biological  Survey, 
a  widespread  interest  in  the  study  and  protection  of  birds  has  done 
much  to  arouse  public  sentiment  and  cause  the  enactment  of  protective 
laws,  such  as  the  McLean  Federal  Bird  Law.  This  campaign  of  educa- 
tion, to  be  noted  later  has  already  begun  to  bear  fruit  and  the  birds 
in  many  localities  are  increasing  in  numbers  in  a  very  gratifying  way. 

There  are  so  many  and  such  excellent  bird  books  and  illustrated 
guides  (see  bibliography)  on  the  market  that  only  a  few  of  the  ways  in 
which  birds  are  of  economic  importance  to  man  will  be  here  noted.  For 
the  same  reason  space  will  not  be  given  to  the  discussion  of  poultry 
and  other  common  domestic  birds,  since  that  is  a  science  in  itself  and 
is  represented  by  a  large  library  of  literature. 

The  classification  of  the  birds  is  so  complicated  and  unsettled  that 
little  will  be  said  of  it  here.  Practically  every  text-book  uses  a  different 
method  from  the  rest,  but  most  authors  divide  the  class,  which  is  es- 
timated to  contain  10,000  to  12,000  species,  into  two  sub-classes:  i. 
Archaeornithes  and  2.  Neornithes.  The  former  contains  the  single 
species  Arch&opteryx  lithographica,  Fig.  112,  the  interesting  Upper 
Jurassic  form  that  possess  the  teeth,  claws,  long  tail,  etc.,  of  the 
reptiles  but  the  feathers  characteristic  of  birds.  It  is  an  excellent  ex- 
ample of  a  connecting  type,  showing  the  descent,  that  is  also  indicated 
in  other  ways,  of  the  birds  from  reptilian  ancestry. 

The  latter  sub-class  contains  the  living  birds,  and  also  a  few  extinct 
forms  which,  while  most  interesting,  have  no  economic  bearing  and 
hence  will  not  be  discussed  here.  The  Neornithes,  in  older  texts, 
are  sometimes  placed  in  two  " Divisions" — A.  Ratitae  and  B.  Carinatae, 
and  as  a  matter  of  convenience,  these  divisions  will  be  used  here. 

The  Ratitae  include  several  extinct  forms,  some  of  great  size,  and  a 


REPTILIA 


179 


few  modern  birds  that  are  characterized,  by  the  absence  or  vestigeal 
character  of  the  wings,  with  corresponding  changes  in  the  structure 
of  the  sternum  (not  keeled),  coracoid  and  other  bones.  They  are  prob- 


PIG.  112. — Archaeopteryx  lithographica.  X/^[.  c,  carpel;  cl,  furcula;  co« 
coracoid;  h,  humerus;  r,  radius;  sc,  scapula;  u,  ulna;  I-IV,  digits.  (From  Hegner' 
College  Zoology,  after  Zittel  from  Steinman  and  Doderlein.} 

ably  degenerated   descendants  of  originally  winged  ancestors.     The 
best-known  representatives  of  this  small  division  are  the  Kiwis  of  New 


180  ECONOMIC  ZOOLOGY 

Zealand,  Fig.  113,  the  Rheas  or  South  American  Ostriches,  and  the 
Struthiones  or  African  Ostriches,  Fig.  114,  to  be  discussed  later. 
In  the  Carinatae  are  included  the  vast  majority  of  modern  birds. 
The  division  is  named  from  the  deep[keel-like  sternum  possessed  by 
most  of  them  which  possess  the  power  of  flight.  While  the  ostriches 
owe  their  safety  to  their  large  size  and  powers  of  rapid  terrestrial  loco- 
motion, and  the  kiwis  to  their  isolation  on  the  Island  of  New  Zealand, 
the  carinatae,  which  are  usually  of  comparatively  small  size,  owe  their 
safety  to  their  almost  universally  highly  developed  power  of  aerial 
flight.  It  is  this  power  that  also  enables  them  to  perform  their  annual 
migrations  and  thus  better  preserve  their  own  lives  and  that  of  their 
young.  This  migration  of  birds  is  one  of  the  most  interesting  subjects 
in  the  field  of  zoology  and  its  bibliography  is  very  extensive. 


FIG.   113. — A    kiwi,    Apteryx    australis.      xKo-     (From    Hegner,    College    Zoology, 

after  Evans.) 

In  a  few  of  the  Carinatae,  the  Penguins,  for  example,  the  wings  are 
developed  into  paddle-like  organs  for  swimming  under  water  and  the 
power  of  aerial  flight  is  entirely  lacking.  A  few  of  the  countless  species 
of  birds  of  economic  importance  will  now  be  discussed,  most  of  which 
species  will  obviously  belong  to  the  division  Carinatae. 

The  Ostrich. — Only  the  African  ostrich,  Struthio  camelus,  will  be 
discussed  here,  since  the  Rheas  or  South  American  ostriches  are  of 
much  less  importance,  though  they  are  hunted  by  the  natives  almost 
to  the  point  of  extinction,  their  feathers  being  useful  for  dusters  and 
other  purposes.  They  are  smaller  than  the  African  forms  but  have 
similar  habits. 

The  African  ostrich  originally  inhabited  all  of  the  more  or  less  desert 
parts  of  the  Dark  Continent  and  certain  regions  of  Southern  Asia. 


AVES 


181 


Authorities  differ  as  to  whether  the  different  forms  all  belong  to  the 
same  species  or  not. 


FIG.   114. — African  or  two-toed  ostrich,  Struthio  camelus.     (Photograph  by  William 
Graham,  from  Jordan  and  Heath,  Animal  Forms.) 

It  is  the  largest  living  bird,  sometimes  reaching  a  height  of  8 
feet    and    weighing   300   pounds.     The   head   and   neck   are    nearly 


1 82  ECONOMIC   ZOOLOGY 

and  the  legs  quite  naked.  The  body  feathers  are  grey  in  the 
hen  and  black  in  the  cock;  those  of  the  tail  and  abortive  wings  are  the 
beautiful  white  plumes  that  have  been  prized  as  ornaments  from  the 
earliest  times. 

In  their  native  haunts  the  ostriches  live  in  flocks  or,  especially  in 
the  breeding  season,  small  groups  of  one  male  and  several  females. 
These  females  all  commonly  lay  in  one  nest  or  hole  in  the  sand  until 
30  or  more  eggs  are  collected;  the  eggs  are  incubated  partly  by  the 
heat  of  the  sun,  partly  by  the  adult  birds,  especially  the  male.  The 
eggs  hatch  in  6  or  8  weeks,  the  speckled  young  being  as  large,  at 
hatching,  as  good-sized  fowls. 

The  male  acts  as  guardian  to  the  flock  and  is  said  to  be  able  to  kill 
a  man  or  even  a  horse  with  a  forward  or  sidewise  kick  of  its  formidable 
two-toed  foot.  Under  domestication  they  become  gentle,  but  each 
ostrich  farm  is  apt  to  have  a  big  male  that  is  said  to  be  "  very  dangerous" 
and  visitors  are  warned  to  keep  at  a  safe  distance;  such  an  animal  adds 
to  the  interest  of  the  exhibit  just  as  a  "man-killer"  lion  does  to  a  travel- 
ling circus. 

They  are,  like  most  birds,  very  wary,  which,  added  to  their  speed, 
which  is  said  to  exceed  that  of  a  swift  horse,  makes  them  difficult  to 
capture.  They  are  sometimes  run  down  by  a  relay  of  horses,  though 
their  habit  of  running  in  a  curve  often  makes  it  possible  to  cut  across 
and  head  them  off.  Traps,  pitfalls,  lassoes,  poisoned  arrows  and  other 
methods  were  used  by  the  natives  to  capture  them.  The  old  story  of 
their  sticking  their  heads  in  the  sand  and  thinking  themselves  hidden 
is,  of  course,  without  foundation  in  observed  fact. 

While  their  natural  food  is  largely  vegetable  they  will  eat  practically 
anything,  including  small  stones  to  aid  the  gizzard  in  grinding  the  food. 
A  favorite  pastime  of  visitors  at  some  of  the  ostrich  farms  is  to  feed 
oranges  to  the  birds,  who  swallow  them  whole  with  ease,  and  the  course 
of  the  orange  down  the  long  oesophagus  may  be  seen  as  a  slowly  moving 
swelling  on  the  animal's  slender  neck.  This  habit  of  eating  anything 
of  suitable  size  for  swallowing  has  doubtless  been  responsible  for  the 
exaggerated  ideas  of  the  ostrich's  phenominal  powers  of  digestion. 
Though  they  can  exist  for  long  periods  without  water,  they  drink 
frequently  when  water  is  at  hand  and  they  are  said  to  be  fond  of  bathing 
up  to  the  neck  in  water. 

The  flesh  is  but  little  used  as  food,  but  the  eggs  are  often  eaten, 


AVES 


183 


one  containing  as  much  food  as  two  dozen  hens'  eggs.  The  shells  are 
used  as  vessels  by  the  natives.  It  is  chiefly  for  the  plumes,  however, 
that  the  ostriches  have  been  hunted  and  have  long  been  domesticated. 
The  oldest  ostrich  farms  are  probably  those  of  South  Africa,  where 
there  are  now  about  half  a  million  tame  birds;  the  annual  output  of 


FIG.    115. — Plucking  an  ostrich.      Note  the  pen  to  confine  the  bird,  and  the  hood  over 
his  head.      (From  Pickrell,  Ostrich  Farming  in  Arizona.) 

these  farms  is  said  to  be  about  $10,000,000.  The  plumes  from  these 
domesticated  birds  are  superior  to  those  of  the  wild  ones.  A  pair 
of  tame  birds  is  worth  from  $700  to  $1000  and  the  net  profits  of  the 
business  in  South  Africa  may  reach  40  per  cent. 


1 84  ECONOMIC   ZOOLOGY 

Ostriches  were  introduced  into  the  United  States  in  1882  and  there 
are  now  farms  in  Florida,  Arizona,  California,  and  elsewhere.  By 
charging  an  admission  fee  these  farms  produce  a  considerable  income 
in  addition  to  that  from  the  plumes. 

The  birds  are  kept  in  fenced  inclosures,  usually  in  trios.  The  eggs 
are  collected  as  laid  and  are  hatched  in  mammoth  incubators.  About 
35  young  per  year  per  trio  are  produced,  though  a  record  of  133  was  made 
in  South  Africa.  As  noted  above,  the  young  are  about  the  size  of  a 
hen  when  hatched,  and  in  six  months  they  have  nearly  reached  the 
adult  size;  they  are  fed  on  chopped  green  alfalfa,  and  are  given  plenty 
of  water.  The  adults  eat  any  sort  of  vegetable  matter.  The  plumes, 
which  grow  on  the  rudimentary  wings  and  tail,  are  clipped  or  plucked, 
without  pain  to  the  birds,  once  or  twice  a  year,  Fig.  115.  Fifty  dollars 
worth  of  plumes  may  be  obtained,  in  some  cases,  from  one  bird  per  year. 
The  body  plumes  are  attractive  but  have,  of  course,  far  less  value 
than  those  from  wings  and  tail.  Plumes  have  been  produced  by 
well-cared-for  individuals  for  35  to  40  years. 

One  of  the  chief  uses  of  birds  has  been,  from  ancient  times,  as  food. 
Nearly  all  species,  unfortunately,  may  be  eaten,  but  the  wild  ducks  and 
geese  are  particularly  desirable,  some  species,  like  the  canvas-back 
duck,  bringing  high  prices.  These  aquatic  forms  have  been  able, 
by  the  aid  of  more  or  less  efficient  game  laws,  to  survive  the  attacks 
of  sportsmen  and  pot  hunters,  but  some  of  our  most  valuable  birds, 
the  quail,  grouse,  etc.,  have  been  hunted,  in  many  sections  of  the 
country,  practically  to  the  point  of  extermination,  and  should  be  pro- 
tected by  a  closed  season  of  indefinite  length. 

On  some  rocky  coasts  the  eggs  of  sea  birds  were  formerly  found  and 
collected  in  enormous  numbers,  until  the  birds  were,  in  many  cases 
nearly  exterminated.  Such  was  the  case  with  the  Murres  of  the  Faral- 
lone  Islands,  off  the  coast  of  California.  The  eggs  of  these  birds  were 
formerly  collected  and  sold  in  San  Francisco  by  the  hundreds  of 
thousands.  Jamaica  is  the  centre  of  a  small  trade  in  " Booby  eggs," 
laid  by  the  Sooty  Tern  and  the  Noddy. 

A  classic  illustration  of  the  extinction  of  a  race  of  animals  by  the 
utterly  ruthless  hunting  of  it  for  food  is  that  of  the  wild  or  passenger 
pigeon.  A  generation  or  two  ago  these  birds  were  found  in  the  States 
west  of  the  Alleghenies  in  numbers  that  surpassed  belief.  They  flew 
in  flocks  that  were  numbered  in  the  millions,  yet,  today  there  is  not,  so 


AVES  185 

far  as  is  known,  a  single  living  passenger  pigeon  in  existence.  It  seems 
probable  that,  with  the  death,  within  the  last  decade,  of  the  single 
specimen  in  the  Cincinnati  zoological  park,  the  species  became  extinct. 
They  were  hunted  during  the  breeding  season,  just  before  the  squabs 
were  able  to  fly;  men  with  their  families,  in  wagons  and  other  vehicles, 
came  for  miles  to  the  woods  where  the  nests  were  built  to  collect  the 
young  birds  which  were  wonderfully  fat.  Trees  were  felled  in  such 
a  way  as  to  bring  down  others  in  their  fall,  and  each  tree  was  loaded 
with  nests  and  young.  The  birds  were  packed  in  boxes,  and  barrels 
and  shipped  to  the  larger  cities  by  the  carload,  sometimes  spoiling 
on  the  way  and  having  to  be  thrown  out.  It  was  this  wholesale 
slaughter  that  totally  exterminated  a  fine  race  of  birds. 

Another  more  unusual  article  of  diet,  derived  from  birds,  is  the  edible 
bird's  nest,  especially  esteemed  by  the  wealthy  Chinese,  some  of  whom 
ascribe  to  it  valuable  tonic  properties  which  it  probably  does  not  have. 
As  is  generally  known  these  nests  are  built  by  swift-like  birds  (genus 
Collocalia)  of  the  Orient  in  rocky  caverns,  usually  along  the  sea,  espe- 
cially in  the  regions  north  of  Borneo.  The  nest  is  of  about  the  size 
and  shape  of  that  of  the  common  chimney  swift  but  consists  of  a  more 
or  less  pure  network  of  dried  secretion  of  the  salivary  glands,  looking 
and  tasting  like  unflavored  gelatin.  The  birds  collect  in  the  caverns, 
some  of  which  are  of  great  extent  and  beauty,  in  enormous  numbers, 
and  the  natives  here  collect  the  nests  by  means  of  ladders  and  ropes, 
each  man  or  group  of  men  assuming  hunting  rights  over  certain  caves 
and  resenting  the  intrusion  of  other  hunters  upon  their  preserves. 

The  nests  sell  at  $12  to  $15  or  more,  per  pound.  The  quality  of  the 
nest  varies;  the  "white"  or  first  quality  nest  consists  of  pure  secretion; 
this  nest  being  removed,  the  bird  builds  another,  into  which  she  may 
introduce  some  foreign  matter  to  help  out  the  diminished  supply  of 
saliva;  this  foreign  matter,  of  course,  detracts  from  the  value  of  the  nest; 
a  third  nest  will  have  still  more  foreign  matter,  while  the  fourth  maybe 
so  contaminated  as  to  be  worthless  as  food;  it  is  probably  this  introduc- 
tion of  foreign  matter  into  the  nests  that  has  saved  the  birds  from  ex- 
tinction. The  annual  value  of  these  jiests  in  some  of  the  small  ports 
of  the  orient  amounts  to  many  thousands  of  dollars. 

The  nests  are  made  into  soups,  jellies,  etc.  The  author  cooked  a 
nest  according  to  the  only  recipe  available  and  found  it  very  tasteless 


1 86  ECONOMIC   ZOOLOGY 

and  insipid;  perhaps  the  Chinese,  who  are  noted  cooks,  are  able  to  give 
it  a  remarkably  desirable  flavor. 

One  of  the  most  ancient  and  widespread  uses  to  which  birds  are  put 
is  for  the  personal  adornment  of  mankind.  This  largely  useless  and 
barbarous  custom,  thanks  to  the  efforts  of  the  Audubon  Society  and 
other  organizations,  is  gradually  disappearing  among  civilized  peoples, 
so  far  as  it  necessitates  the  killing  of  birds  for  the  sake  of  their  plumage. 

One  of  the  best,  or  rather  worst,  illustrations  of  the  lengths  to  which 
man  will  go  along  these  lines  is  to  be  seen  in  the  famous  Bishop  Museum 
in  Honolulu,  H.  I.  There  are  here  to  be  seen  the  royal  robes  made  of 
yellow  feathers  and  said  to  be  worth  hundreds  of  thousands  of  dollars. 
The  yellow  feathers  for  these  robes  were  obtained,  it  is  said,  from  a  small 
patch  of  yellow  feathers  on  the  breast  of  a  bird  about  the  size  of  a  robin. 
The  numbers  of  these  small  birds  that  must  have  been  slaughtered  to 
obtain  the  thousands  of  feathers  in  each  of  these  gorgeous  robes  can  be 
imagined,  as  each  patch  of  yellow,  so  far  as  the  writer  can  remember, 
was  not  greater  in  area  than  a  square  centimeter.  The  wearing  of 
aigrets  by  women  in  the  so-called  "best  society"  was  a  custom  hardly 
less  barbarous,  since,  as  is  now  generally  known,  these  aigrets  were  the 
nuptial  plumes  of  the  white  herons,  Fig.  116,  Ardea  egretta  and  other 
species,  to  obtain  which  the  adults  were  slaughtered  during  the  breed- 
ing season,  which  often  left  the  young  to  die  of  starvation  after  the 
parent  birds  were  killed.  These  beautiful  birds  were  once  to  be  seen 
by  the  thousands,  in  the  south,  while  now  one  may  travel  the  swamps 
for  days  without  seeing  one.  Fortunately  the  government  has  at 
last  taken  a  hand  in  the  protection  of  the  egrets  against  this  useless 
slaughter,  and  perhaps  in  time  they  may  again  become  abundant. 

Another  group  of  beautiful  birds  that  man  formerly  hunted  most 
ruthlessly  for  their  plumage  are  the  Birds  of  Paradise.  The  natives 
of  the  Orient  hunted  them  with  blunt  arrows,  with  snares,  with  bird- 
lime and  in  other  ways,  and  civilized  (?)  man  used  his  superior  weapons 
to  destroy,  still  more  rapidly,  these  wonderfully  beautiful  creatures. 
Fortunately  public  sentiment  and  federal  laws  are  now  beginning  to 
frown  upon  this  kind  of  slaughter  and  perhaps  the  Paradise  birds  may 
be  saved  from  the  fate  of  the  passenger  pigeon. 

An  important  avian  product  is  guano,  a  most  valuable  fertilizer 
found  on  certain  islands  and  coasts  of  the  South  Pacific,  especially  on 
the  Chincha  Islands,  off  the  coast  of  Peru.  This  material  consists  of  the 


AVES  187 

dried  excrement  of  numberless  sea  birds  (usually),  deposited,  during 
long  ages  in  a  practically  rainless  region.  On  the  Chincha  Islands  the 
deposits  were  as  much  as  100  feet  thick,  but  they  have  now  been  depleted. 
These  large  fish-eating  sea  birds  congregate  at  certain  places  in  in- 
credible numbers  and  with  no  rain  to  wash  it  away  the  excremental 
matter  would  collect  indefinitely.  The  term  guano  is  applied  also  to 


PIG.  116. — American  egret,  Ardea  egretta.  Length,  41  inches.  Photograph 
from  specimen  with  neck  extended.  (From  Dougherty,  Principles  of  Economic 
Zoology.) 

the  collected  excrement  of  bats,  sometimes  found  in  caves,  and  to  ferti- 
lizers artificially  made  from  certain  fishes — menhaden  for  example 
— after  extracting  the  oil. 

A  number  of  birds  are  of  some  importance  as  scavengers,  though  per- 
haps their  usefulness  in  this  particular  way  has  been  exaggerated.  The 


1 88 


ECONOMIC   ZOOLOGY 


best  known  of  our  North  American  scavengers  are  the  carrion  crows, 
or  black  vultures  and  the  turkey  buzzards  or  vultures.  The  former, 
Catharista  atrata,  is  the  smaller  of  the  two  and  is  common  in  the  vil- 


T 


FIG.    117. — California    quail,   Lophortyx   californicus.      X;Hj«     (From   Jordan   and 
Heath,  Animal  Forms.) 

lages  and  towns  of  the  Southern  States,  especially  along  the  coasts. 
It  flies  about  the  streets  feeding  upon  refuse,  and  often  becomes  quite 
tame. 

The  turkey  buzzard,  Cathartes  aura,  whose  majestic  flight  is  familiar 
to  most  people  in  the  rural  sections  of  the  United  States  has  been  con- 


AVES  189 

sidered  of  such  value  as  a  scavenger  that  it  has  been  protected,  by 
some  States,  by  a  fine  for  killing  it.  Of  recent  years,  however,  the 
opinion  is  held  by  many  that  the  buzzards  and  perhaps  crows  are  far 
more  injurious  than  beneficial  since  they  apparently  are  conveyors  of 
the  germs  of  hog  cholera  and  possibly  other  diseases  of  domestic  animals. 
It  is  possible,  then,  that  a  bounty  rather  than  a  fine  should  be  placed  on 
the  head  of  the  turkey  buzzard.  The  way  in  which  the  buzzards  locate 
an  animal  so  shortly  after  its  death  has  always  been  a  mystery,  some 
authors  holding  the  birds  are  guided  by  a  remarkably  keen  sense  of 
smell,  others  that  it  is  an  equally  remarkable  sense  of  sight.  It  is 
usually  thought  that  it  is  a  matter  of  sight,  and  that  when  one  bird 
locates  the  carcass  and  begins  to  investigate  in  smaller  and  smaller 
circles,  the  other  birds,  noting  these  actions,  are  attracted  toward  the 
same  locality  until  often  a  considerable  number  will  congregate  to  feed 
upon  the  carcass  of  a  comparatively  small  animal;  Chapman  says  both 
sight  and  smell  are  used. 

In  the  far  South  the  carrion  crows  and  buzzards  often  congregate 
upon  the  trees  under  which  hunters  are  skinning  the  alligators  they 
have  killed  during  the  preceding  night,  and  as  soon  as  a  carcass  is 
thrown  away  the  birds  drop  to  the  ground  and  begin  to  tear  at  the 
flesh  and  viscera.  The  writer  once  made  use  of  such  a  flock  of  birds 
to  " rough  up"  the  skeleton  of  a  6-foot  alligator.  After  removing  the 
skin  and  the  viscera  the  body  was  thrown  on  the  grass  just  outside 
of  the  camp;  in  a  few  hours  the  birds  had  picked  off  the  meat  so  nicely 
that  the  skeleton  had  simply  to  be  rubbed  over  with  salt  (NaCl)  to 
make  it  fit  to  be  shipped  home  as  a  "rough  skeleton"  ready  for  the 
taxidermist. 

On  the  Pacific  coast  the  California  vulture  or  "  Condor, "  Gymno- 
gyphs  calif ornianus,  is  found  in  very  small  numbers.  It  is  a  magnificent 
bird  with  '.a  spread  of  wings  of  from  8  to  n  feet,  and  is  rigidly 
protected  by  law. 

The  relation  of  birds  to  agriculture  is  an  extensive  subject  in  itself 
and  it  can  be  merely  touched  upon  here,  along  some  of  its  more  im- 
portant lines. 

There  are  two  ways  in  which  birds  are  of  especial  benefit  to  agri- 
culture: as  destroyers  of  insects  and  as  eaters  of  weed  seeds.  The 
former  is  universally  recognized;  the  latter  is  not  so  generally  appre- 
ciated. A  great  deal  of  investigation  has  been  carried  on,  during  recent 


i  go 


ECONOMIC  ZOOLOGY 


years,  upon  the  food  of  our  common  birds.  In  determining  the  eco- 
nomic status  of  any  bird  it  is  necessary  to  know  of  what  its  food  consists 
at  all  seasons  of  the  year.  A  bird  may  be  a  nuisance  for  a  few  weeks, 
as  a  fruit  eater,  for  example,  while  all  the  rest  of  the  year  it  may  be 
highly  beneficial  to  the  farmer  as  an  eater  of  weed  seeds  and  of  destruc- 
tive insects. 

The  food  of  birds  is  determined  in  two  ways:  the  more  pleasant 
but  less  accurate  method  is  to  watch  them  feed  and  note  what  they  eat; 
the  less  pleasant  but  more  accurate  method  is  to  kill  the  birds  at  dif- 


PIG.  118. — The  hairy  woodpecker,  Dryobates  villosus,  at  breakfast.  X;Hj. 
(From  Daugherty,  Principles  of  Economic  Zoology,  after  Biological  Survey,  U.  S, 
Dept.  of  Agriculture.) 

ferent  seasons  and  in  different  places  and  examine  carefully  the  stomach 
contents.  The  latter  method,  which  has  been  extensively  employed 
by  the  Biological  Survey  of  the  Department  of  Agriculture,  gives  not 
only  the  kinds  of  foods  eaten  but  the  proportions  of  each  kind.  By  such 
studies  it  has  been  determined  that  while  few  species  of  birds,  perhaps, 
are  entirely  beneficial,  the  vast  majority  of  our  common  birds  do  far 


AVES 


IQI 


more  good  than  harm  and  should,  therefore,  for  purely  economic  reasons 
be  protected.  In  a  few  cases  the  good  and  bad  traits  are  so  equally 
balanced  that  it  is  difficult  to  decide  upon  the  economic  status  of  the 
,species;  and  in  still  fewer  cases  the  bad  traits  clearly  overbalance  the 
good  ones  and  the  species  are  rated  as  pests. 

Another  way  in  which  birds  are  of  great  benefit  to  agriculture,  and 
one  that  needs  emphasizing  more  than  the  others,  is  in  the  destruction  of 
field  mice  and  other  rodent  pests,  to  be  discussed  later.  The  birds  that 
do  this  valuable  work  are  the  various 
species  of  hawks  and  owls.  The 
latter  being  nocturnal  are  more  or 
less  free  from  the  danger  of  man's 
firearms;  but  the  former  are  almost 
universally  considered,  by  farmers 
and  others  to  be  pests,  since  some  of 
them,  at  times,  do  destroy  young 
poultry  and  beneficial  birds.  The 
owls  being  nocturnal  are  especially 
adapted  to  feed  on  rodents  which 
are  also  largely  nocturnal  in  habits, 
and  with  the  possible  exception  of 
the  Great  Horned  Owl,  they  are  all 
considered  to  be  beneficial  birds. 

The  Great  Horned  Owl,  Bubo 
mrginianus,  Fig.  119,  is  a  large 
species,  nearly  2  feet  long,  with 
prominent  ear-tufts  that  give  the 
appearance  of  horns;  it  lives  in  less 
populous  regions  and  destroys  poul- 
try and  birds  in  considerable  num- 
bers, but  often  counterbalances  this 
damage  by  the  destruction  of  rabbits 
that,  in  many  places,  are  a  pest,  as  will  be  noted  later. 

Fisher  (143)  found  that,  "Of  127  stomachs  (of  the  owl)  examined, 
31  contained  poultry  or  game  birds;  8,  other  birds;  13,  mice;  65,  other 
mammals;  i,  a  scorpion;  i,  a  fish;  10,  insects;  and  17  were  empty." 
It  will  be  seen  that  of  these  stomachs  only  39  contained  birds  while  78 


PIG.   119. — Great  horned  owl,  Bubo 
virginianus.      X%. 


192 


ECONOMIC   ZOOLOGY 


contained  mammals  and  10,  insects;  surely  the  balance  here  seemed  to 
be  in  the  owl's  favor. 

The  Barn  Owl,  Strix  pratincola,  Fig.  120,  the  Screech  Owl,  Mega- 
scops  asio,  and  some  others  are  specially  useful  species.  . 

As  a  general  proposition,  then,  the  owls  should  by  all  means  be 
protected  and  encouraged  in  every  way. 

The  record  of  the  hawks, 
while  not  so  good  as  that  of  the 
owls,  is  far  better  than  is  popu- 
larly supposed.  They,  too,  live 
largely  upon  rodent  pests  and  a 
few  of  them  also  destroy  poultry 
and  beneficial  birds. 

The  hawk-like  birds  that  are 
considered  by  ornithologists  to  be 
more  destructive  than  beneficial 
are  as  follows:  the  Gyrfalcons 
(genus  Falco)  which  are  essen- 
tially arctic  forms ;  the  Duck  Hawk, 
Falco  peregrinus  anatum,  ranging 
over  North  America,  especially 
near  water,  where  it  is  destruc- 
tive to  water  fowl;  the  Sharp- 
shinned  Hawk,  Accipiter  velox, 
breeding  throughout  the  United 
States  and  destroying  birds  and 
poultry;  Cooper's  Hawk,  A. 
cooperi,  Fig.  121,  similar  to  but 
larger  than  the  Sharp-shinned 
and  especially  destructive  to  poul- 

American  Goshawk,  A .  atricapillus,  is  a  still  larger  species 
breeding  north  of  the  United  States  and  wintering  as  far  south  as 
Virginia. 

The  hawks  most  commonly  known  as  Hen  Hawks  or  Chicken  Hawks 
are  the  Red-tailed,  Buteo  borealis,  and  the  Red-shouldered,  B.  lineatus. 
These  large  hawks,  common  in  Eastern  North  America,  are  generally 
blamed  for  the  loss  of  poultry  really  due  to  Cooper's  Hawk  or  one  of  the 
other  species.  In  studying  the  food  of  hawks,  Fisher  found  in  connec- 


PIG.  1 20. — Barn  owl,  Strix  pratin- 
cola. X/i-  Photograph  from  specimen. 
(From  Daugherty,  Principles  of  Economic 
Zoology.} 

try;    the 


AVES 


193 


tion  with  the  Red-tailed  Hawk  that  "Of  562  stomachs  examined,  54 
contained  poultry  or  game  birds;  51,  other  birds;  278,  mice;  131,  other 
mammals;  37,  batrachians  or  reptiles;  47,  insects;  8,  crawfish;  i, 
centiped;  13,  offal;  and  89  were  empty."  It  will  be  noted  that  456 
stomachs  of  the  562  examined  contained  mammals  and  insects,  so  that 
this  much-maligned  bird  evidently  does  much  more  good  than  harm, 
in  spite  of  its  occasional  theft  of  small  poultry. 


FIG.   121. — Cooper's  hawk,  A ccipiter  cooperi.      X%. 

Since  so  very  few  people  are  able  to  recognize  the  few  destructive 
species  of  hawks,  especially  on  the  wing,  it  would  seem  much  the  better 
plan  to  "play  safe"  and  leave  them  all  alone. 

As  an  illustration  of  the  losses  sometimes  caused  by  ignorance  of 
the  real  habits  of  animals,  especially  birds,  Chapman  (139)  quotes 
as  follows  from  the  1886  report  of  C.  Hart  Merriam,  then  Ornithologist 
and  Mammalogist  of  the  United  States  Department  of  Agriculture: 

"On  the  23d  of  June,  1885,  the  Legislature  of  Pennsylvania  passed  an 
act  known  as  the  'scalp  act,'  ostensibly  'for  the  benefit  of  agriculture,'  which 
provides  a  bounty  of  50  cents  each  on  hawks,  owls,  weasels  and  minks  killed 
within  the  limits  of  the  State,  and  a  fee  of  20  cents  to  the  notary  or  justice 
taking  the  affidavit. 

13 


I Q4  ECONOMIC  ZOOLOGY 

"By  virure  of  this  act  about  $90,000  has  been  paid  in  bounties  during 
the  year  and  a  half  that  has  elapsed  since  the  law  went  into  effect.  This 
represents  the  destruction  of  at  least  128,571  of  the  above-mentioned  animals, 
most  of  which  were  hawks  and  owls. 

"Granting  that  5000  chickens  are  killed  annually  in  Pennsylvania  by 
hawks  and  owls,  and  that  they  are  worth  25  cents  each  (a  liberal 
estimate  in  view  of  the  fact  that  a  large  proportion  of  them  are  killed  when 
very  young),  the  total  loss  would  be  $1250,  and  the  poultry  killed  in  a  year 
and  a  half  would  be  worth  $1875.  Hence  it  appears  that  during  the  past 
eighteen  months  the  State  of  Pennsylvania  has  expended  $90,000  to  save 
farmers  a  loss  of  $1875.  But  this  estimate  by  no  means  represents  the 
actual  loss  to  the  farmer  and  the  tax-payer  of  the  State.  It  is  within  the 
bounds  to  say  that  in  the  course  of  a  year  every  hawk  and  owl  destroys  at 
least  a  thousand  mice  or  their  equivalent  in  insects,  and  that  each  mouse  or 
its  equivalent  so  destroyed  would  cause  the  farmer  a  loss  of  two  cents  per 
annum.  Therefore,  omitting  all  reference  to  the  enormous  increase  in  the 
numbers  of  these  noxious  animals  when  Nature's  means  of  holding  them  in 
check  has  been  removed,  the  lowest  possible  estimate  of  the  value  to  the 
farmer  of  each  hawk  and  owl  would  be  $20  a  year,  or  $30  in  a  year  and  a 
half. 

"Hence  in  addition  to  the  $90,000  actually  expended  by  the  State  in 
destroying  128,571  of  its  benefactors,  it  has  incurred  a  loss  to  its  agricultural 
interests  of  at  least  $3,857,130,  or  a  total  loss  of  $3,947,130  in  a  year  and 
a  half,  which  is  at  the  rate  of  $2,631,420  per  annum.  In  other  words  the  State 
has  thrown  away  $2,105  for  every  dollar  saved.  And  even  this  does  not  rep- 
resent fairly  the  full  loss,  for  the  slaughter  of  such  a  vast  number  of  predaceous 
birds  and  mammals  is  almost  certain  to  be  followed  by  a  corresponding 
increase  in  the  number  of  mice  and.  insects  formerly  held  in  check  by  them, 
and  it  will  take  many  years  to  restore  the  balance  thus  blindly  destroyed 
through  ignorance  of  the  economic  relations  of  our  common  birds  and 
mammals."  Fortunately  this  law  was  soon  repealed. 

As  noted  above  there  are  a  few  birds  which  do  more  harm  than  good 
and  a  few  whose  economic  value  has  not  been  definitely  determined. 
As  an  example  of  the  former  group  the  English  Sparrow  stands  out. 
Introduced  into  this  country  first  at  Brooklyn,  N.  Y.,  in  1850,  and  later 
into  various  States,  the  House  Sparrow,  popularly  named  from  the 
country  whence  it  was  brought,  has  spread  over  practically  the  entire 
country  and  parts  of  Canada.  It  is  supposed  to  have  been  introduced 
for  two  main  reasons:  to  destroy  certain  insects  then  damaging  crops 
and  for  sentimental  reasons  by  persons  of  foreign  birth  who  wanted  to 


AVES  IQ5 

see  a  familiar  European  bird  in  this  country.  Its  introduction  into 
America  is  an  excellent  illustration  of  the  danger  of  introducing  an 
animal  into  a  new  environment  which  may  prove  so  favorable  that 
the  animal  will  increase  in  numbers  to  the  extent  of  being  a  pest. 
This  is  exactly  what  has  happened  in  the  case  of  the  English  Sparrow, 
which  is  considered  such  a  pest  that  various  methods  of  extermination 
have  been  suggested  and,  usually,  unsuccessfully  tried.  What  will  be 
the  final  outcome  it  is  difficult  to  foresee.  It  is  claimed  by  some  that 
98  per  cent,  of  the  food  of  this  sparrow  is  vegetable  and  that  74  per  cent. 
is  grain.  It  also  damages  fruits  and  young  flower  buds.  It  is  pugna- 
cious and  quarrelsome  and  by  occupying  the  available  nesting  places 
tends  to  drive  away  other  small,  valuable  birds.  It  has  a  tendency  to 
live  about  houses  which  it  often  soils  in  a  very  annoying  way.  It  is  of 
some  slight  value  about  towns  as  a  scavenger  and  possibly  does  some 
good  as  a  destroyer  of  insects  and  weed  seeds,  but  the  total  balance 
seems  to  be  strongly  against  it.  As  the  writer  knows  from  personal 
experience  it  may  be  kept  away  from  individual  homes  in  the  country 
by  a  ceaseless  warfare,  killing  the  adults  with  a  .22  calibre  rifle,  using 
shot  cartridges,  and  destroying  the  nests  as  fast  as  built. 

The  American  crow,  Corvus  americanus,  one  of  the  most  familiar 
of  all  our  birds,  is  very  generally  considered  by  farmers  to  be  a  pest 
because  of  its  habit  of  eating  newly  planted  corn  and  other  grain,  not 
to  mention  eggs  and  small  chickens;  but  it  is  not  at  all  certain  that  it 
does  not  much  more  than  pay  for  this  loss  in  the  insects  and  other  pests 
that  it  destroys,  throughout  the  year,  which  are  said  to  constitute 
more  than  23  per  cent,  of  his  diet.  By  most  people  the  common  or 
American  crow  is  not  distinguished  from  the  considerably  larger  species 
of  the  same  genus,  the  northern  raven,  nor  from  the  somewhat  smaller 
species  the  fish  crow. 

The  jays,  especially  the  common  blue  jay,  Cyanocitta  cristata,  are 
another  group  of  familiar  birds  whose  economic  value  is  very  doubtful 
on  account  of  their  habit  of  destroying  the  eggs  and  young  of  other 
birds;  but  along  with  these  highly  undesirable  habits,  they  have  others 
that  are  of  benefit  to  man. 

In  some  sections  the  blackbirds  or  grackles  (genus  Quiscalus) 
are  considered  a  pest  because  of  the  damage  they  do  to  ripening  corn, 
late  in  the  summer;  it  is  probable  again  that  this  damage  is  more  than 


196 


ECONOMIC  ZOOLOGY 


atoned  for  by  the  insects  and  weed  seeds  destroyed  during  the  rest  of 
the  year. 

There  is  one  way  in  which  our  winter  birds  do  a  wonderfully  im- 
portant work;  it  is  in  the  destruction  of  great  numbers  of  insect  larvae 


:: 


FIG.  122. — Fotir  common  seed-destroying  sparrows:  i,  Junco;  2,  white-throated 
sparrow;  3,  fox  sparrow;  4,  tree  sparrow.  (From  Daugherty,  Principles  of  Economic 
Zoology,  after  Bulletin  17,  Biological  Survey,  U.  S.  Dept.  of  Agriculture.) 

that  are  hidden  under  the  bark  of  trees  and  in  all  sorts  of  out-of-the- 
way  places.     During  the  cold  months  when  adult  insects  are  lacking 


AVES  197 

and  vegetable  food  is  scarce  our  winter  residents  fairly  comb  the  trees 
for  these  wintering  larvae,  which  must  be  carefully  hidden  to  escape  the 
sharp  eyes  of  the  hungry  birds. 

It  is  obvious  then  that  every  means  should  be  employed  to  protect 
and  encourage  our  native  birds,  and  some  of  the  ways  in  which  this 
may  be  done  will  be  briefly  described.  Two  main  lines  may  be  followed 
in  bird  preservation;  (i)  control  of  bird  enemies  and  (2)  direct  protec- 
tion and  encouragement  of  the  birds  themselves. 

According  to  Forbush  the  numbers  of  birds  in  Pennsylvania  de- 
creased over  50  per  cent,  in  15  years;  this  decrease  was  due  largely, 
though  not  entirely,  to  their  destruction  by  their  enemies,  chief  of 
whom  is  man.  Man,  the  worst  enemy  of  all  living  things,  has  killed 
birds  by  the  m'llion,  for  food,  for  plumage  and  for  mere  wanton  sport. 
Man  also  includes  the  small  boy,  and  the  boy  that  is  not  so  small, 
who  not  only  kills  birds  with  guns  and  other  weapons  but  who  also 
robs  the  nests,  in  the  collection  of  bird  eggs,  a  habit  that  should  be 
discouraged  in  every  possible  way.  Perhaps  the  worst  offenders 
against  the  bird  life  of  the  country  are  the  foreign  laborers,  who 
slaughter  indiscriminately  every  bird,  large  and  small,  that  comes 
within  range.  Vigorous  laws  against  hunting  on  Sundays  have  helped 
diminish  this  nuisance,  and  other  game  laws,  to  be  discussed  later, 
have  done  much  to  save  many  species  from  extinction.  Man  has 
also  done  much,  unintentionally,  to  diminish  the  bird  population  by 
clearing  woodlands  and  thickets,  draining  swamps,  etc. 

Of  the  so-called  natural  enemies  of  birds  the  house  cat  is  probably 
the  most  destructive,  especially  the  half-wild  kind  that  is  seen  about 
every  farm,  village  and  city.  It  is  estimated  that  cats  kill,  on  an 
average,  from  10  to  50  birds  each  year;  if  only  10  per  year  are  killed 
the  total  for  the  State  of  Massachusetts  would  probably  be  about 
700,000.  Another  estimate  gives  the  total  birds  killed  by  cats  at 
31,000,000  per  year.  Whatever  the  number  may  be  it  is  probable 
that  cats  destroy  more  birds  than  all  the  other  animals  (excluding  man) 
combined.  Although  of  value  as  destroyers  of  rats  and  mice,  in  some 
cases,  as  will  be  noted  later,  it  is  probable  that  the  country  would  be 
better  off  if  the  race  of  domestic  cats  were  exterminated.  Many  a 
farmer  that  will  kill  a  cat  for  catching  a  very  occasional  small  chicken 
seems  to  pay  no  heed  whatever  to  the  continual  destruction  of  birds,  by 
the  dozen  or  more  cats  about  the  place. 


IQ  ECONOMIC   ZOOLOGY 

Dogs,  foxes,  minks,  etc.,  destroy  some  birds,  but  probably  not  to  a 
very  serious  extent;  the  value  of  the  latter  two  as  rodent  destroyers 
will  be  discussed  later.  Some  squirrels,  especially  the  red  squirrel, 
destroy  considerable  numbers  of  eggs  and  young  birds,  but  since  they 
also  eat  insects  their  economic  status  is  perhaps  uncertain. 

Rats  and  mice  do  some  damage,  especially  to  birds  nesting  on  the 
ground  and  about  human  habitations.  Hawks,  especially  Cooper's 
and  the  sharp-shinned  varieties,  destroy  many  birds  and  if  recognized 
as  belonging  to  these  destructive  species  they  should  be  killed.  Owls 
kill  some  birds,  but,  as  already  pointed  out,  most  of  them  are  so  valuable 
as  destroyers  of  rodents  that  they  more  than  pay  for  the  birds  they 
destroy. 

Crows,  jays  and  shrikes  sometimes  do  considerable  damage  to 
the  eggs  and  young  of  other  birds;  and  one  who  has  seen  a  shrike 
empale  a  sparrow  or  some  other  small  bird  on  a  thorn  and  then  delib- 
erately tear  it  to  pieces  and  eat  it  will  not  have  much  love  for  the 
butcher  bird. 

Certain  snakes  are  accused  of  eating  birds  and  bird  eggs,  but, 
like  the  owls,  it  is  probable  that  most  species  more  than  make  up 
for  the  birds  eaten  by  the  destruction  of  rodent  and  other  animal  pests. 

It  is  seen,  then,  that  the  two  worst  enemies  of  birds  are  man  and 
the  domestic  cat,  both  of  whom  could  and  should  be  controlled,  the 
former  by  law,  the  latter  by  a  marked  reduction  in  numbers  if  not  by 
extermination. 

Encouragement  of  Birds. — To  encourage  birds  and  thereby  increase 
their  numbers  a  number  of  things  may  be  done,  some  of  which  will  be 
briefly  noted:  i.  Forbid  their  being  shot,  both  in  season  and  out,  by 
adults  and  by  boys,  and  especially  by  ignorant  foreigners  and  negroes. 
Aid  in  the  passage  of  suitable  laws  for  the  protection  of  all  sorts  of  game, 
especially  birds.  Although  largely  through  selfish  motives,  the  sports- 
men of  the  country  long  ago  saw  the  necessity  of  protecting  game  birds, 
and  as  early  as  1791  New  York  enacted  a  law  protecting  certain  game 
birds.  Only  recently  have  the  farmers  begun  to  see  the  necessity  of 
stringent  game  laws  to  protect  birds,  and  now  we  not  only  have  state 
laws  but  we  are  beginning  to  have  federal  laws,  like  the  McLean  Mi- 
gratory Bird  Law  that  protects  migratory  birds  wherever  found,  with 
the  idea  that  a  bird  that  moves  from  one  part  of  the  country  to  another 
belongs  to  the  country  as  a  whole  and  not  to  any  one  state  where  it  may 


AVES 


199 


spend  a  few  weeks  or  months  each  year.     The  passage  of  this  law  was 
one  of  the  greatest  advances  of  the  age  in  bird  protection.     Before  its 


(From   Dearborn,  [Bird 


PIG.  123.  FIG.  124. 

PIG.   123.  —  Bird   house    made    from    hollow    log.      X%. 
Houses  and  How  to  Build  Them.) 

FIG.   124.  —  Gourd  for  wrens  or  bluebirds.    X^-     (From  Dearborn,  Bird'jHouses} 
and  How  to  Build  Them. 


passage  a  reed  bird,  for  example,  might  have  been  protected  in  Vir- 
ginia, but  as  soon  as  it  crossed  the  North  Carolina  boundary  it  could  be 
slaughtered  in  any  numbers. 

By  a  treaty  with  Canada,  effective  July  31, 
1918,  migratory  birds  are  given  not  «nly  national, 
but  international  protection.  The  various  regu- 
lations of  this  treaty  define  the  means  by  which 
migratory  game  birds  may  be  taken,  the  open 
season  for  certain  birds,  bag  limits,  etc. 

The  killing  at  any  time  in  the  United  States 
of  the  following  birds  is  forbidden  by  law  :  band- 
tailed  pigeon,  common  ground  doves  and  scaled 
doves,  little  brown  crane,  sandhill  crane,  whoop- 
ing crane,  wood  duck,  swans,  curlews,  willet,  up- 
land plover,  all  shore  birds  (except  black-bellied 
and  golden  plovers,  Wilson  snipe  or  jacksnipe, 
woodcock,  and  the  greater  and  lesser  yellow- 
legs),  bobolinks,  catbirds,  chicadees,  cukoos,  flickers,  flycatchers, 


FIG.  125. — Tomato 
can,  with  one  end  re- 
moved, fastened  to  top 
of  post.  Hole  cut  in 
side  for  entrance.  Suit- 
able for  bluebirds  or 
wrens  if  put  in  shady 
place.  (From  Dearborn, 
Bird  Houses  and  How 
to  Build  Them.) 


200  ECONOMIC  ZOOLOGY 

grossbeaks,  humming  birds,  kinglets,  martins,  meadow  larks,  night 
hawks  or  bull-bats,  nuthatches,  orioles,  robins,  shrikes,  swallows, 
swifts,  tanagers,  titmice,  thrushes,  vireos,  warblers,  waxwings,  whip- 
poor-wills,  woodpeckers,  wrens,  all  other  perching  birds  which  feed 
entirely  or  chiefly  on  insects;  also  auks,  auklets,  bitterns,  fulmars, 
gannets,  grebs,  guillemots,  gulls,  herons,  jaegers,  loons,  murres,  pet- 
rels, puffins,  shearwaters  and  terns. 

The  various  states  have  game  laws  of  various  degrees  of  string- 
ency for  the  protection  of  their  local  resident  birds,  that  is,  the  birds 
that  do  not  migrate  and  hence  do  not  receive  protection  under  the  Mc- 
Lean law.  For  example  there  is  generally  a  closed  season  during  which 
these  birds  cannot  be  killed;  often  a  limit  is  set  upon  the  number  of 
birds  that  may  be  killed  in  one  day  and  in  an  entire  season;  a  license, 
either  free  or  to  be  bought,  is  often  required  for  each  hunter;  unnatural- 
ized  foreigners  and  minors  under  a  certain  age  are  sometimes  for- 
bidden to  hunt;  hunting  on  Sundays  is  sometimes  forbidden;  occasion- 
ally an  animal  becomes  so  scarce  that  a  closed  season  for  a  term  of  years 
is  declared,  thus  giving  the  species  a  chance  to  recuperate  if,  as  may 
happen,  the  closed  season  has  not  been  too  long  delayed.  There  are 
many  birds  that  should  be  thus  given  a  chance  to  recuperate  by  a  long 
if  not  perpetual  closed  season;  for  example,  the  quail  one  of  our  most 
useful  insect  and  weed  destroyers,  should,  in  many  states,  doubtless 
be  given  a  long  if  not  a  permanent  protection  against  sportsmen. 

2.  Destroy  useless  cats  and  dogs,  especially  in  small  towns  and  in 
the  country;  the  destructiveness  of  cats  has  already  been  noted,  their 
claims  to  usefulness  will  be  discussed  later. 

3.  Discourage  the  use  of  bird  ornaments;  this  is  largely  accom- 
plished now  by  federal  laws  that  absolutely  protect  certain  birds  by 
making  the  possession  of  their  plumes  a  felony. 

4.  Organize  Audubon  and  other  societies  to  excite  popular  interest 
in  birds  and  to  offer  possible  aid  in  securing  suitable  legislation. 

5.  Stop  the  collection  of  bird  eggs  by  youthful  or  even  older  col- 
lectors, unless  for  some  well-established  scientific  institution. 

6.  Educate  the  public,  especially  the  children  who  will  be  the 
hunters  of  the  future,  by  lectures,  bird-days  in  schools,  etc.     It  is  here 
that  the  teachers  in  secondary  schools  can  and  do  accomplish  a  great 
work,  by  bringing  up  the  next  generation  to  be  lovers  and  students; 
rather  than  hunters  of  birds. 


AVES 


2OI 


7.  Preserve  old  trees,  posts,  and  an  occasional  thicket  in  which  birds 
are  in  the  habit  of  nesting,  and  erect  boxes  and  other  nesting  devices 
for  them  in  suitable  places.  The  character  of  the  boxes  will  vary  with 
the  birds  that  it  is  desired  to  attract,  and  their  architecture  may  be 
infinitely  varied.  Old  tin  cans,  hollow  logs,  gourds,  etc.,  may  be  easily 
made  over  to  suit  bird  tenants,  Fig.  123,  124  and  125,  or  if  more  orna- 
mental structures  are  desired,  the  birds  will  not  object  after  the  paint 
is  dry  and  the  newness  has  worn  off.  Plans  for  bird  houses  are  given 
in  various  government  bulletins  and  elsewhere.  Unless  it  is  desired 


r 


FIG.   126. — A  martin  house.       xMo-     (From  Dearborn,  Bird  Houses   and   How  to 
Build  Them.     This  pamphlet  gives  details  of  construction.) 


to  attract  martins,  the  only  house  birds  that  are  social,  the  houses  are 
built  for  one  pair  only. 

In  many  localities  it  is  quite  a  common  custom  to  build  many-roomed 
and  often  ornate  houses  for  the  use  of  the  purple  martin,  Prague  subis. 
Such  houses,  Fig.  126,  are  usually  attached  to  the  top  of  a  pole,  12  to 
15  feet  high;  the  rooms  are  about  6X6X6  inches  in  size.  With  such 
a  house  a  colony  of  martins  may  sometimes  be  started  from  an  over- 
crowded colony  several  miles  away.  They  are  not  only  cheerful, 


202 


ECONOMIC   ZOOLOGY 


interesting  birds,  but  they  are  extremely  useful  as  destroyers  of  insects 
which  they  capture  on  the  wing. 

8.  Supply  food,  especially  in  the  winter;  and  nesting  material, 
water,  etc. ,  in  the  summer.  To  protect  the  birds  while  feeding  or  to  keep 
the  food  from  being  covered  with  snow,  various  kinds  of  plat- 
forms and  food  houses  have  been  constructed  usually  with  the  idea  of 


PIG.  127. — Pood  shelf  outside  of  window,  so  arranged  that  birds  may  be  watched 
from  the  room  within.  (From  McAtee,  How  to  Attract  Birds  in  Northwestern 
United  States.) 

allowing  the  birds  to  be  seen  while  feeding,  Fig.  127,  128,  129  and  130. 
Where  water  is  scarce  mud  may  be  provided  for  the  use  of  robins  and 
other  birds  that  use  it  in  building  their  nests. 

Where  birds  that  are  otherwise  useful  are  destructive  to  small  fruits 
and  berries  they  may  be  attracted  away  from  these  fruits  by  planting 
about  the  orchard,  for  their  especial  Juse,  various  wild  or  uncultivated 


AVES 


203 


species  such  as  the  mulberry,  service  berry,  Virginia  creeper,  elder- 
berry, holly,  various  wild  grapes,  etc. 

Some  of  the  above  methods  of  encouraging  bird  life  are  more  impor- 
tant than  others  and  their  importance  will  vary  in  different  localities, 
but  all  will  help,  more  or  less,  to  increase  the  numbers  of  this  most 
useful  and  attractive  group  of  animals. 

Another  method  of  encouraging  bird  life  which  is  of  very  great  im- 
portance, but  which  only  a  few  people  are  financially  able  to  indulge 


FIG.  128. — A  feeding  box  attached  to  the  top  of  a  pole.  It  is  open  at  the 
bottom  but  has  glass  sides  and  a  tight  roof.  (From  McAtee,  How  to  Attract  Birds 
in  Northwestern  United  States.) 

in,  is  the  establishment  of  bird  preserves.  To  be  sure  every  farmer 
who  absolutely  forbids  the  killing  of  birds  on  his  farm  is  maintaining 
a  small  and  useful  bird  preserve;  but  there  are  being  established,  from 
time  to  time,  large  tracts  of  land  for  this  purpose  whose  value  to  the  bird 
life  of  the  country  is  incalculable.  An  example  of  such  a  preserve  is 
Marsh  Island,  near  New  Orleans.  This  is  a  tract  of  some  75,000  acres, 
purchased  by  Mrs.  Russell  Sage  and  given  by  her  to  the  United  States 
as  a  refuge  for  birds  during  their  stay  in  the  south  in  the  winter  or  through- 


2O4 


ECONOMIC   ZOOLOGY 


out  the  year.  In  this  reservation  where  formerly  the  birds  were 
slaughtered  by  the  thousands  by  pot-hunters  and  sportsmen  there  is 
now  a  safe  refuge  where  the  native  birds  may  rear  their  young  and  where 
the  migrants  from  the  North  may  safely  spend  the  winter. 

In  conclusion,  let  every  intelligent  person  use  his  influence  in  all 
possible  ways  to  protect  the  birds.     Public  sentiment  is  fast  tending 


FIG.  129.  FIG.  130. 

FIG.  129. — A  feeding  box  pivoted  on  a  pole  so  that  the  open  side  will  be  away 
from  the  direction  of  the  wind.  (From  McAtee,  How  to  Attract  Birds  in  Northwestern 
United  States.) 

FIG.   130. — Food  tray   made  from   a  barrel  top    and   hoops   fastened   to   top   of 
pole.     (From  McAtee,  How  to  Attract  Birds  in  Northwestern  United  States.) 

in  this  direction  and  there  is  yet  time  to  prevent  the  almost  total  ex- 
tinction of  song  birds  that  has  taken  place  in  some  countries.  By  prop- 
erly educating  the  coming  generation  it  should  be  possible  to  produce 
a  public  frame  of  mind  that  would  consider  the  unnecessary  slaughter 
of  birds  as  the  real  crime  that  it  is. 


CHAPTER  XIV 
MAMMALIA 

Of  all  the  classes  of  the  animal  kingdom  the  mammals  are  the 
highest,  using  that  term  in  a  broad  sense,  since  it  includes  man,  whose 
high  mental  development  has  given  him  dominion  over  the  rest  of  the 
animate  world.  Economically  it  is  doubtless  the  most  important 
class  of  animals  since  it  includes,  among  others,  our  domestic 
quadrupeds. 

The  name  mammal  has  been  derived  from  the  presence,  in  all 
members  of  the  class,  of  milk-secreting  glands  or  mammae  for  the 
nourishment  of  the  young;  these  glands  vary  in  development  from  the 
rudimentary  organs  of  the  Monotremes  to  the  enormous  udders  of 
high-grade  milk  cows. 

The  other  chief  characteristic  of  the  class  is  the  presence,  at  some 
period  of  life,  of  hairs,  which  are  almost  as  characteristic  of  mammals 
as  feathers  are  of  birds;  these  hairs  vary  from  the  soft  fur  of  moles 
or  seals  to  the  long  quills  of  the  porcupine;  like  feathers  they  are  of 
epidermal  origin  and  like  them  also  they  are,  in  many  cases,  periodically 
shed  and  replaced. 

Other  epidermal  structures  are  often  highly  developed,  such  as 
claws,  hoofs  and  teeth,  the  last-named  being  almost  universally  present 
and  in  two  sets,  the  "milk"  and  "permanent"  teeth.  The  variation 
in  bodily  size  among  the  Mammalia  is  enormous,  extending  from  the 
tiny  mice  and  shrews,  2  or  3  inches  long  to  the  largest  whales, 
which  may  reach  a  length  of  80  feet  or  more  and  are  probably 
the  bulkiest  animals  the  world  has  ever  produced,  though  not  the 
longest. 

With  very  few  exceptions  the  ovum  of  mammals  is  of  microscopic 
size  and  is  developed  within  the  uterus  of  the  parents,  to  which  it 
is  attached  and  from  which  it  derives  its  nourishment  by  means  of  a 
vascular  structure  the  placenta. 

Unlike  the  birds  but  few  mammals  migrate,  but  a  number  of  them 

205 


206  ECONOMIC  ZOOLOGY 

hibernate  in  a  dormant  condition  in  some  hidden  place  and  thus  pass 
the  cold,  foodless  season,  their  warm  blood  and  covering  of  hair  pro- 
tecting them  against  the  cold.  The  red  blood  corpuscles  of  almost  all 
mammals  are  circular  discs,  without  nuclei.  In  all  but  two  or  three 
small  groups  all  mammals  have  seven  cervical  vertebrae. 

The  number  of  known  species  of  living  mammals  is  variously  stated. 
Henshaw,  in  1912,  estimated  the  number  at  7000;  other  authorities 
place  the  number  even  higher. 

The  classification  of  the  Mammalia,  unlike  that  of  the  birds  is 
pretty  well  established.  By  most  authors  they  are  divided  into  two 
subclasses:  (i)  Prototheria  or  egg-laying  mammals  and  (2)  Eutheria 
or  viviparous  mammals. 

Under  the  first  subclass  is  included  but  one  order,  the  Monotremata ; 
under  the  second  subclass  fall  all  the  higher  mammals  including,  of 
course,  man. 

As  has  been  said  this  is  economically  the  most  important  of  all  the 
groups  of  animals,  though  there  is  very  great  variation  in  the  relative 
importance  of  the  orders.  These  orders  will  now  be  taken  up  in  turn 
but  not  in  order  of  their  economic  importance. 

Monotremata.  Duckbill  and  Spiny  Anteater. — These  animals  are 
commonly  known  as  the  egg-laying  mammals  from  the  fact  that  they 
lay  eggs  like  those  of  birds  and  reptiles,  the  young  being  nourished  by 
the  yolk  of  the  egg  instead  of  through  the  placenta,  as  in  other  mam- 
mals. They  are  small  animals,  18  to  24  inches  in  length,  found  only 
in  the  region  of  Australia  and  New  Zealand.  Their  name  is  derived 
from  the  fact  that  the  urogenital  organs  and  intestine  open  into  one 
cavity,  the  cloaca,  as  in  birds  and  reptiles;  they  have  other  reptilian 
characteristics,  also.  The  presence  of  hair  and  rudimentary  mammary 
glands  causes  them  to  be  classed  as  mammals.  The  two  best  known 
species  of  this  small  order  are  the  duckbill  or  platypus,  Ornithorhynchus , 
and  the  spiny  ant-eater,  Echidna.  These  forms,  though  most  in- 
teresting zoologically,  have  but  little  economic  importance.  The 
former  doubtless  is  of  value  as  an  insect  eater,  the  latter  is  used  for 
food  to  some  extent. 

Marsupialia.  Kangaroos  and  Opossums. — The  chief  character- 
istic of  this  order  and  the  one  from  which  the  name  is  derived  is  the 
possession  of  a  marsupium  or  pouch  of  skin  on  the  ventral  abdominal 
wall;  in  this  pouch  the  young,  which  are  born  in  a  very  immature 


MAMMALIA 


207 


condition,  are  placed  by  the  parent,  and  they  remain  there,  attached 
to  the  mammary  glands,  until  more  fully  developed. 

The  best  known  representatives  of  this  rather  small  group  are 
the  opossums,  Fig.  131,  of  America  and  the  kangaroos  and  wallabies 
of  Australia,  Fig.  132. 

The  Virginia  opossum,  Didelphis  virginiana,  is  common  in  the 
southern  and  middle  states.  It  is  a  grey,  thick-bodied  animal  of 
about  the  size  of  a  large  cat;  it  has  a  rat-like,  but  prehensile,  tail.  It  is 


FIG.    131.  —  The   opossum,    Didelphis^virginiana. 

Zoology.) 


(From    Hegner,    College 


frequently  hunted  and  used  as  food,  the  flesh  being  of  a  very  agreeable 
taste.  Its  flesh  is  supposed  to  be  especially  popular  with  the  negroes. 

The  kangaroos  and  wallabies  vary  in  size  from  that  of  a  small 
cat  to  5  feet  or  more  in.  height.  Their  small  anterior  legs  are  used 
as  hands  and  the  animals  usually  progress  by  a  series  of  leaps,  using 
for  this  purpose  the  strong  hind  legs  and  large  tail.  There  are  about 
60  species  of  these  Australian  forms. 

The  kangaroos  are  vegetarians  and  at  times  may  be  injurious  to 


208 


ECONOMIC  ZOOLOGY 


grass  intended  for  feeding  cattle.  They  are  extensively  hunted  both 
for  their  hides,  from  which  leather  is  made,  and  for  their  flesh  which  is 
excellent,  especially  that  of  the  hind  legs  and  tail.  A  large  specimen  may 
weigh  200  pounds.  The  flesh  is  said  to  resemble  venison.  As  is 


PIG.   132. — Kangaroo,  Macropus  robustus.      X/fo- 

so  often  the  case  the  animals  are  being  hunted  almost  to  extermination 
in  many  places. 

Insectivora.  Moles  and  Shrews. — This  is  a  group  of  small 
mammals  usually  with  soft  hair  or  fur.  Their  projecting  front  teeth 
and  sharp-pointed  back  teeth  enable  them  to  sieze  and  eat  insects 


MAMMALIA  2OQ 

upon  which  they  chiefly  live.  They  are  the  most  primitive  of  the 
placental  animals.  They  are  absent  from  Australia  and  from  most 
of  South  America.  They  are  mostly  terrestrial  and  nocturnal  in 
habits;  many  are  subterranean;  some  are  aquatic  and  some  arboreal. 
The  two  North  American  families  are  the  Talpidce,  the  moles,  and  the 
Soricida,  the  shrews.  The  common  mole,  Scalopus  aquaticus,  Fig.  133, 
is  the  familiar,  soft-furred  animal,  about  6  inches  long,  without  external 
ears,  with  rudimentary  eyes,  and  with  huge  hand-like  front  feet  that  it 
uses  in  burrowing  just  beneath  the  surface  of  the  ground.  This  is  one 
of  the  most  useful  and  least  appreciated  of  our  common  animals.  On 
closely  trimmed  lawns  it  sometimes  makes  a  nuisance  of  itself  by  up- 


FIG.   133. — Common  mole,  Scalopus  aquaticus.      X%.     (Courtesy  of  the  Biological 

Survey.) 

heaving  the  sod  above  its  tunnels,  but  in  the  fields  and  gardens  it  does 
an  immense  amount  of  good  by  eating  cut-worms  and  other  insects 
destructive  to  vegetation. 

It  is  almost  universally  considered  by  farmers  to  be  destructive 
to  vegetation  because  its  burrows  are  not  distinguished  from  those  of 
that  most  destructive  rodent,  known  as  the  Pine  Mouse,  to  be  discussed 
later.  It  should  be  remembered  that  this  mole  is  an  insect-eating 
not  a  plant-eating  animal  and  it  should  not  be  blamed  for  the  destruction 
of  young  plants,  newly  planted  corn,  potatoes,  etc.,  which  are  often 
seriously  damaged  by  field  mice. 

The  shrews  are  much  less  well  known  than  the  moles.  They  are 
small  mouse-like  animals  with  long,  pointed  snouts.  Some  of  them 

14 


210  ECONOMIC   ZOOLOGY 

are  the  smallest  of  all  mammals.  They  usually  live  on  the  ground  or 
in  holes  and  [are  easily  mistaken  for  [mice.  While  their  habits  are 
not  very  well  known  they  are  doubtless  valuable  insect  destroyers. 

Moles  are  sometimes  used  as  food,  but  their  small  size  and  com- 
paratively small  numbers  makes  them  of  no  importance  in  this  way. 

Hedgehogs  are  sometimes  used  as  food.  They  may  be  covered  with 
a  layer  of  clay,  which  peels  off,  when  the  animal  is  removed  from  the 
fire,  bringing  the  spines  of  the  animal  with  it.  The  hedgehog  is  not 
found  in  North  America. 

Chipptera.  Bats. — The  bats  are  at  once  recognized  by  their  large 
membranous  wings,  the  digits  of  the  fore-legs  being  enormously  elon- 
gated and  connected  by  thin  membranes  of  skin.  Their  power  of  flight 
has  caused  them  to  be  widely  distributed,  often  in  places  inaccessible 
to  other  mammals.  There  are  more  than  600  species  of  bats, 
varying  from  a  few  inches  in  expanse  of  wings  to  5  feet,  in  the  "  flying 


FIG.   134. — Little  brown  bat,  Myotis  lucifugus  (Vespertilio  subulatus.)      X%. 

foxes"  of  the  Orient.  They  are  usually  nocturnal  and  spend  the  day 
hanging  head-down  in  some  cave  or  other  dark  place.  In  certain  lime- 
stone caves  they  may  be  found  hibernating  in  enormous  numbers. 
They  fly  through  the  intricate  and  totally  dark  passages  of  these  caverns 
with  perfect  ease  and  certainty,  owing  to  the  possession  of  a  certain 
marvelously  acute  tactile  sense  that  warns  them  of  their  near  approach 
to  solid  bodies. 

A  few  large  oriental  and  other  tropical  bats  are  fruit-eaters  and 
are  quite  destructive  to  figs  and  other  tropical  fruits,  especially  since 
they  often  travel  about  in  groups. 

Most  bats,  however,  are  insectivorous,  and,  being  nocturnal  in  habits, 
destroy  many  forms  that  would  not  ordinarily  fall  prey  to  birds.  It  is 


MAMMALIA  211 

evident,  then,  that  our  ordinary  bats  should  not  be  molested  but 
should  be  encouraged.  The  experiment  has  been  tried  of  furnishing 
them  with  artificial  shelters  in  which  to  spend  the  day,  hoping  in  this 
way  to  encourage  them  to  remain  in  a  given  locality. 

Among  the  commoner  bats  of  the  United  States  are  the  Little  Brown 
Bat,  Myotis  lucifugus,  Fig.  134,  the  Red  Bat,  Lasiurus  (Atalapha) 
noveboracensis ,  each  about  3^  inches  long  and  the  Brown  Bat, 
Eptesicus  fuscus,  a  slightly  larger  form. 

In  some  way  two  statements  about  the  common  bats  have  become 
current;  first,  that  they  often  entangle  themselves  in  women's  hair, 
and  second,  that  they  bring  bedbugs  into  houses.  I  have  questioned 
many  men  and  women  and  have  not  found  a  single  one  who  ever  knew 
of  a  specific  case  where  a  bat  had  become  entangled  in  human  hair. 
I  have  also  examined  many  bats,  on  one  or  two  occasions,  in  the  caves 
where  they  were  hibernating  'by  the  thousand,  but  never  was  a  bed- 
bug and  seldom  was  any  kind  of  a  parasite  seen.  They  are  not  very 
attractive  little  animals,  since  they  bite  quite  vigorously  and  often  have 
an  unpleasant  animal  odor,  but  they  are  quite  inoffensive  if  unmolested 
and  are,  as  has  been  said,  highly  beneficial  as  insect  destroyers. 

In  the  regions  where  they  abound,  the  large  fruit-eating  bats  are 
sometimes  killed  for  their  skins  which  are  covered  with  soft  fur. 

The  Vampire  Bats  are  inhabitants  of  South  America;  they  injure 
horses  and  cattle  and  other  animals,  especially  the  young,  by  sucking 
their  blood.  It  is  reported  that  they  may  even  attack  a  sleeping  human 
being,  fanning  him  with  their  wings  to  insure  sound  slumbers,  while 
they  puncture  the  skin  of  the  victim's  foot  with  their  sharp  front  teeth 
and  then  suck  or  lap  the  blood.  The  author  does  not  vouch  for  this 
story,  however,  especially  the  part  about  fanning  the  sleeper  with  their 
wings.  Beebe,1  tells  of  sleeping  in  Guiana  with  Vampires  flying  in  the 
room  without  being  molested;  but  White1  reports  being  bitten  on  the 
foot,  while  sleeping,  by  one  of  these  bats,  and  advises  sleeping  under 
nets. 

Carnivora.  Flesh-eating  Mammals. — While  most  of  the  carniv- 
ora,  as  the  name  would  indicate,  are  flesh-eaters,  some  are  omnivorous 
and  a  few  are  vegetarians.  The  teeth  of  this  order  form  the  most 
marked  characteristic  of  this  group.  The  incisors  are  usually  small 
and  weak;  the  canines,  or  "eyeteeth,"  on  the  contrary,  are  long, 

1  Tropical  Wild  Life  in  British  Guiana.     N.  Y.  Zool.  Society,  1917. 


212  ECONOMIC  ZOOLOGY 

sharp  and  curved,  and  aid  their  possessor  in  seizing  and  holding  his 
struggling  prey;  the  premolars  and  molars  are  adapted  for  cutting  and 
grinding  flesh,  so  that  by  means  of  these  teeth  a  cat  may  be  able  to 
chew  a  tough  piece  of  meat  that  a  human  being  could  scarcely  eat  at  all. 
Most  of  the  carnivora,  at  least  of  the  terrestrial  forms,  have  sharp  claws 
that  aid  in  the  capture  of  food  and  in  self-defense;  the  canine  teeth 
also  are,  of  course,  important  weapons  of  offense  and  defense.  The 
carnivora  include  most  of  our  so-called  "fur-bearing"  animals. 

The  dozen  or  more  families  of  this  order  are  usually  grouped  into 
two  sub-orders:  the  Fissipedia  or  Carnivora  Vera,  including  a  large 
number  of  forms  that  are  chiefly  terrestrial;  and  the  Pinnipedia,  a 
much  smaller  group  of  aquatic  forms,  such  as  the  seal,  sea-lion,  walrus, 
etc.,  to  be  discussed  later. 

The  families  of  Fissipedia  occurring  in  the  Western  Hemisphere, 
north  of  Mexico,  with  the  approximate  number  of  species  of  each 
(according  to  Hornaday)  are  as  follows: 

Canidae  (dog,  fox,  wolf,  etc.) 22 

Felidaj  (cats) 8 

Ursidse  (bears) 12 

Mustelidae  (marten,  mink  skunk,  etc.) 46 

Procyonidae  (raccoon) 3 

The  economic  value  of  the  Carnivora  is  chiefly  due  to  their  soft 
hair  or  fur,  though  there  are  other  ways  in  which  they  have  considerable 
economic  importance,  for  example  in  the  destruction  of  cattle. 

According  to  the  Biological  Survey  there  is  an  annual  loss  of  more 
than  $20,000,000  due  to  the  destruction  of  livestock,  chiefly  on  the 
western  ranges,  by  wolves,  coyotes,  mountain  lions  and  other  predatory 
animals. 

The  Government,  in  cooperation  with  the  states,  is  conducting  a 
great  campaign  against  these  and  other  animal  pests,  in  which  probably 
more  than  $1,000,000  annually  is  being  expended. 

Predatory  animals  are  destroyed  by  poisoning,  trapping,  shooting  and 
den  hunting  during  the  breeding  season.  In  this  work  from  250  to  350 
hunters  are  employed  under  district  inspectors;  about  one-fifth  of 
these  hunters  are  paid  by  the  states  or  by  local  organizations  and 
individuals.  The  skins  taken  by  Federal  hunters  become  the  property 
of  the  Government,  with  a  total  value  during  the  last  year  of  probably 
$100,000. 


MAMMALIA  213 

Canada  may,  perhaps,  be  said  to  owe  her  start,  commercially,  to 
the  fur  trade.  In  the  early  days  there  was  almost  no  limit  to  the  profits 
of  the  fur  business,  since  the  Indians  from  whom  they  were  chiefly 
obtained,  did  not  appreciate  the  value  of  the  skins  they  sold,  and  the 
early  traders,  "coureurs  des  bois, "  became  a  most  unscrupulous  and 
disreputable  class  of  men.  In  1670  the  Hudson  Bay  Company  was 
chartered,  with  extensive  and  exclusive  privileges,  and  the  sign  of 
this  company  is  still  a  familiar  sight  along  the  Canadian  Pacific  Railroad, 
though  it  is,  of  course,  not  merely  a  firm  for  handling  furs.  Since  the 
fur-bearing  animals  are  apt  to  be  inhabitants  of  colder  regions,  many, 
if  not  the  majority,  of  them  are  captured  in  Canada  and  the  Northern 
States  of  the  Union,  though  there  are  some  valuable  forms  taken  in 
the  Southern  States. 

The  American  furs  are  usually  superior  to  the  European  and  millions 
of  dollars  worth  are  exported  each  year,  while  large  numbers  are  im- 
ported into  the  United  States. 

"In  the  fiscal  year  ending  June  30,  1917,  the  foreign  trade  of  the  United 
States  in  raw  and  manufactured  furs  reached  nearly,  if  not  fully,  the  high 
level  of  the  years  preceding  the  war.  The  imports  were  valued  at  $21,553,375, 
while  the  exports  amounted  to  $15,729,160,  a  sum  exceeded  in  only  one 
previous  year,  1913,  when  they  were  $18,389,586"  (176). 

While  it  is  difficult  to  obtain  accurate  figures  on  the  number  of  skins 
handled  each  year,  the  following  quotation  from  a  personal  letter  from  Mr. 
E.  W.  Nelson,  Chief  of  the  Bureau  of  Biological  Survey,  will  give  an  idea  of 
the  number  and  value  of  some  American  forms: 

"Funsten  Bros,  of  St.  Louis,  Mo.,  offered  at  their  three  auction  sales 
during  1917,  5,345,000  American  skins.  At  the  March  and  October  auction 
sales  of  the  New  York  Fur  Auction  Sales  Corporation,  2,152,900  American 
skins  were  offered.  Whether  these  skins,  nearly  8,000,000,  were  all  taken  in 
1917  is  not  known.  Probably  they  were  not,  but  a  large  proportion  of 
American  skins  do  not  pass  through  these  two  channels.  At  Funsten's 
three  1917  sales  there  were  offered  3,110,000  muskrat  skins  which  brought 
from  $0.06  to  $0.91  each;  586,000  opossum  skins,  which  brought  from  $0.0 1 
to  $1.1 8  each;  446,000  skunk  skins  which  brought  from  $0.10  to  $4.35; 
314,000  raccoon  skins,  which  brought  from  $0.35  to  $7.00  each;  186,000 
ermine  skins,  which  brought  from  $0.10  to  $2.75  each;  155,000  mink  skins, 
which  brought  from  $0.20  to  $11.50;  42,000  lynx  skins  which  brought  from 
$1.00  to  $26.50  each;  37,955  beaver  skins,  which  brought  from  $1.25  to 
$15.25  each;  and  33,050  red  fox  skins,  which  brought  from  $1.75  to  $33.50 
each." 


214  ECONOMIC   ZOOLOGY 

The  frequent  changes  in  fashion  that  cause  wide  fluctuations  in 
market  prices  are  probably  the  salvation  of  many  species  of  fur-bearing 
animals  by  giving  them  a  chance  to  recuperate  during  the  periods  when 
their  hides  are  not  in  demand. 

The  preparation  of  most  skins  for  shipment  is  easy;  they  are  simply 
cleaned  of  fat  and  meat  and  are  dried  in  a  cool  place. 

Fur  Farming. — It  is  probable  that  almost  any  of  the  fur-bearing 
animals  may  be  profitably  raised  in  captivity;  as  a  matter  of  fact  a 
number  of  them,  the  fox,  skunk,  muskrat,  and  others,  are  already  so 
raised,  the  colder  latitude  of  Canada,  especially  along  the  coasts,  being 
the  most  suitable  region  for  many  of  them.  The  necessary  conditions, 
of  course,  vary  with  the  species,  and  the  habits  of  the  animals  to  be 
handled  must  be  carefully  studied.  There  are  several  reasons  for 
encouraging  the  domestication  of  the  fur-bearing  animals  besides 
merely  as  a  profitable  venture. 

In  the  first  place  unless  they  be  so  raised  manyof  them  will  doubtless 
become  extinct.  Again  the  old  methods  of  the  trapper  were  very  waste- 
ful, many  pelts  being  damaged  by  the  traps  and  by  larger  carnivorous 
animals  that  fed  on  the  smaller  ones  caught  by  the  traps;  these  methods 
were  wasteful  also  in  catching  and  killing  many  animals  whose  fur 
was  not  in  good  condition.  Lastly — 

"Apart  from  economic  considerations  the  cruelty  involved  in  trapping 
wild  animals  affords  a  powerful  argument  against  the  continuation  of  the 
practice.  Trapping  is  notoriously  cruel  and  tends  to  destroy  the  finer  feelings 
of  those  engaged  in  the  business. 

"  Trappers  visit  their  lines  only  two  or  three  times  a  week,  and  in  the 
interval  the  captured  animals,  in  most  cases  suffering  excruciating  pain,  are 
exposed  to  frost,  hunger,  their  natural  enemies,  and  finally,  their  arch- 
enemy— man  .  .  .  When  it  is  remembered  that  millions  of  animals  are 
captured  yearly  in  traps  the  sum  total  of  their  suffering  must  be  so  great  that 
the  cruelty  practised  on  dumb  domestic  animals,  which  so  greatly  concerns 
the  Society  for  the  Prevention  of  Cruelty  to  Animals,  must  seem  slight  in 
comparison.  The  methods  of  killing  domestic  animals  are  humane  and 
painless,  and  it  would  seem  that  humane  considerations  alone  present  a 
sufficient  argument  for  the  domestication  of  fur-bearing  animals  (162)." 

According  to  Jones  the  first  fur-bearing  animals  to  be  raised  under 
domestication  were  the  various  Karakul  sheep,  Fig.  135,  whose  lambs, 
for  a  few  weeks  (during  which  time  they  are  killed)  have  the  tightly 


MAMMALIA 


215 


curled  black  or  gray  wool  characteristic  of  the  " Persian  lamb,"  "astra- 
khan," "krimmer,"  etc.,  of  furriers.  These  animals  were  originally 
raised  in  the  Karakul  and  other  districts  of  West  Turkestan,  but  the 
industry  has  now  spread  to  eastern  and  central  Europe  and  even  to 
Africa  and  America.  It  is  interesting  to  note  that  it  is  here  the  very 


PIG.  135. — Karakul  sheep  and  very  young  lamb,  the  latter  showing  desired 
tight,  uniform,  and  lustrous  curl,  evenly  distributed  all  over  the  body.  The  ewe 
is  an  imported  Karakul.  (From  Marshall,  Heller,  and  McWhorler,  Karakul  Sheep.) 

young  lambs  that  are  killed  for  their  hides.  If  a  very  tight  curl  is 
desired  the  lamb  is  killed  within  three  or  four  days  of  birth;  if  a  more 
open  curl  is  wanted,  the  lamb  is  allowed  to  live  for,  perhaps,  five  or  six 
weeks.  As  the  skin  of  a  three-day-old  lamb  may  bring  $5  or  more  it 
would  seem  that  the  raising  of  these  animals  should  be  highly  profitable. 
As  an  illustration  of  the  methods  of  fur  farming  a  brief  description 
of  those  employed  in  rearing  foxes  in  captivity  will  suffice. 


2l6 


ECONOMIC  ZOOLOGY 


The  skin  of  the  ordinary  red  foxes  (genus  Vulpes)  may  be  worth  from 
$5  to  $15  or  more.  The  silver  fox,  Fig.  136,  which  is  simply  a  color 
phase  of  the  red  fox,  has  fur  which  may  be  silvery  or  jet  black  in  color 


FIG.   136. — A  full  furred  black  fox,  Vulpes  sp.,  December  fur. 
Fur  Farming  in  Canada.) 


(From  Jones, 


and  is  of  such  beautiful  quality  that  a  good  hide  seldom  brings  less 
than  $500  and  frequently  is  worth  $2000;  the  highest  price  ever  paid 
for  a  single  black  fox  skin  is  said  to  be  $2900.  At  the  minimum  figure, 


MAMMALIA 


217 


it  is  evident,  there  must  be  large  profits  in  fox-raising  and,  in  fact, 
fortunes  ha've  thus  been  made,  though  the  business  is  a  pretty  risky 


one.  Many  millions  of  dollars  are  now  invested  in  fox  farms.  Since 
$25,000  or  more  may  have  to  be  paid  for  a  single  pair  of  breeders  it  is 
evident  that  a  considerable  capital  is  necessary  to  finance  the  business. 


218 


ECONOMIC  ZOOLOGY 


One  of  the  chief  centres  for  raising  silver  foxes  is  Prince  Edward  Island, 
Canada;  the  cold,  moist  climate  and  good  breeding  stock  produce 
pelts  of  high  grade,  while  the  surrounding  water  makes  it  easy  to  capture 
any  foxes  that  may  escape  from  the  pens. 

The  best  location  for  a  ranch  is  a  well-drained  piece  of  woodland, 
with  underbrush  beneath  which  the  foxes  can  sleep  without  being  seen; 
the  trees  give  shade  in  summer  and  warmth  in  winter. 


FIG  138. — Usual  type  of  kennel  and  pen.     Pox  seated  at  entrance.     (From  Jones, 
Fur  Farming  in  Canada.) 


The  individual  pen  is  of  varying  size,  usually  about  40  feet  square, 
sometimes  with  a  part  in  which  the  male  may  be  confined  during  cer- 
tain periods  when  he  might  injure  the  females  or  young.  The  pen  is 
surrounded  by  a  wire  fence  8  or  10  feet  high,  with  an  overhang 
to  prevent  the  foxes  from  climbing  over,  and  a  buried  portion  or 
concrete  base  to  prevent  their  digging  beneath  to  freedom.  Around  the 
pen  or  group  of  pens  is  an  outer  fence.  The  arrangement  of  such  a 
ranch  is  shown  in  Fig.  137.  In  the  pen  is  a  kennel  for  protection  in 


MAMMALIA 


2IQ 


cold  weather,  made  of  wood  or  concrete,  with  a  double  wall,  filled  in 
with  cork  or  some  other  non-conducting  material.  In  this  warm  re- 
treat the  young  are  born  during  the  spring  months  after  a  gestation 
period  of  about  50  days.  One  male  can  be  used  to  mate  with  several 
females.  One  litter  of  from  one  to  nine  pups  are  born  each  year,  sexual 
maturity  being  reached  in  10  months. 

The  foxes  are  killed  in  November  or  December  when  about  eight 
months  old.  To  obviate  injury  to  the  skin,  the  foxes  are  often  killed 
either  by  crushing  the  chest  or  by  breaking  the  neck.  There  is  not 
the  slightest  excuse  for  these  cruel  methods,  especially  the  former, 


FIG.   139. — Canadian  otters,  Lutra  canadensis. 

in  Canada.) 


(From  Jones,  Fur  Farming 


since  a  small  quantity  of  chloroform  or  of  ether  could  be  used  at  a 
nominal  cost. 

Since  the  value  of  the  skin  depends  both  on  the  cold  climate  and  on 
good  health,  the  character  of  the  food  is  important.  Contrary  to  popu- 
lar belief,  the  fox  is  far  from  being  a  strictly  carnivorous  animal,  and  a 
very  general  diet  of  meat,  fish,  mice,  rabbits,  birds,  vegetables,  grass, 
berries,  eggs,  milk,  bread,  dog  biscuits,  etc.,  is  often  employed.  Like 
other  animals,  the  fox  is  subject  to  certain  diseases  and  the  rancher 
who  is  raising  animals  as  valuable  as  the  silver  fox,  needs  to  make  a 
careful  study  of  the  whole  business  before  he  begins.  Great  care  has 
to  be  taken  not  only  to  prevent  the  escape  of  the  animals  from  the  pens 


22O 


ECONOMIC   ZOOLOGY 


but  to  keep  poachers  from  stealing  the  foxes;  for  this  purpose  watch- 
men, dogs,  burglar  alarms,  electric  lights,  electric  shocking  devices, 
bear  traps,  etc.,  are  employed. 

The  natural  appearance  of  the  interior  of  a  fox  pen  is  shown  in  Fig. 
138,  with  a  fox  at  the  entrance  of  the  kennel.  According  to  Jones 
there  were  800  silver  foxes  in  captivity  in  Canada  in  1912. 


PIG.   140. — The    mink,    Putorius    vison. 

Canada.) 


(From    Jones,   Fur    Farming   in 


Otters,  minks  and  skunks,  Figs.  139,  140,  141,  though  the  value  of 
their  skins  may  be  stated  in  cents  where  that  of  the  silver  fox  is  given 
in  dollars,  are  all  raised  profitably  under  domestication. 

Although  not  a  member  of  the  order  Carnivora,  attention  should 
here  be  called  to  the  muskrat,  Fiber  zibethicus,  Fig.  142,  perhaps  the 
most  important  of  our  fur-bearing  animals,  certainly  if  numbers  be 
considered.  When  properly  prepared,  the  fur  of  this  animal  is  very 
fine  and  is  popular  under  the  name  of  " Hudson  Bay  Seal."  About 
10,000,000  muskrat  pelts  are  sold  annually.  The  muskrat  is  generally 
distributed  along  the  water  courses  of  North  America.  In  the  salt 


MAMMALIA  221 

marshes  along  the  Chesapeake  and  Delaware  Bays  muskrats  are  pro- 
tected and  collected  in  large  numbers,  50  rats  per  acre  per  year  being 
secured  in  favorable  places.  They  may  be  fenced  in  with  wire  netting 
and  given  food  and  artificial  shelter.  Not  only  is  the  pelt  of  value 
but  the  flesh  at  certain  seasons  is  sold  as  "marsh  hare"  or  "marsh 
rabbit"  and  is  canned.  The  musk  is  also  sold. 

Like  other  rodents,  the  muskrat  breeds  rapidly  producing  three  to 
five  litters  of  from  three  to  ten  or  more  young  each  year.  They  prob- 
ably breed  at  the  age  of  six  months.  Occasionally,  the  muskrat  becomes 
a  pest  to  the  farmer  and  has  to  be  reduced  in  numbers. 


FIG.   141. — Skunk,  Mephitis  sp.       X%.     The  skin  of  this  animal  is  a   "long  stripe,  " 

or  rather  wide  No.   3. 

Another  rodent,  the  largest  of  our  American  forms,  the  beaver, 
Castor  canadensis,  Fig.  143,  is  a  fur-bearer  of  considerable  importance. 
Formerly,  largely  used  in  the  manufacture  of  beaver  hats,  it  is  now 
chiefly  used  as  plucked  fur,  in  muffs,  etc. 

The  above  and  many  other  furs  are  sold  either  under  their  own  or  a 
trade  name,  the  latter  being  given  because  of  popular  prejudice  against 
the  real  animal  from  which  the  fur  came.  In  many  cases  the  fur  is 
clipped  and  dyed  out  of  all  resemblance  to  its  original  appearance. 
Some  of  these  names  are  considered  by  reputable  dealers  to  be  per- 
missible, others  are  actual  misnomers  and  are  given  with  the  intention 
of  deceiving  the  purchasers.  Among  the  former  some  of  the  better 
known  are  the  following,  the  actual  name  being  given  first,  the  trade 
name  second:  goat  (dyed) — bear  goat;  mink  (dyed) — sable  mink; 
opossum  (sheared  and  dyed) — beaver  opossum;  muskrat  (pulled 


222 


ECONOMIC  ZOOLOGY 


and  dyed) — Hudson  Bay  seal;  rabbit  (sheared  and  dyed) — seal  coney; 
white  rabbit — mock  ermine;  skunk — black  marten.  Among  the 
actual  misnomers  for  the  use  of  which  dealers  may  be  prosecuted  are  the 
following:  muskrat  (pulled  and  dyed) — seal;  rabbit  (sheared  and 
dyed) — seal;  muskrat  (dyed) — mink  or  sable;  white  rabbit,  ermine; 
white  rabbit  (dyed)  chinchilla;  goat  (dyed) — bear;  etc. 

Ponies,  lambs,  kids,  puppies  and  cats  are  used  in  large  numbers  in 
the  fur  trade. 

The  subject  of  furs  and  fur-bearers  is  a  large  one  and  for  further 
information  the  reader  is  referred  to  special  monographs  and  trade 
journals. 


FIG.   142. — Muskrat,  Fiber  zibethicus.       X%. 

The  lions,  tigers  and  leopards,  inhabitants  of  warm  climates, 
though  not  usually  thought  of  in  connection  with  the  fur-bearers,  have 
considerable  value  in  this  way,  but  their  destructiveness  to  cattle  or 
even  to  human  life  makes  them  of  more  negative  than  positive  value. 

Although  the  carnivora  are  not  very  generally  used  for  human  food, 
yet  some  of  them  such  as  bears,  seals,  etc.,  are  often  so  used.  The  skins 
of  certain  bears  are  also  valuable  and  those  of  certain  seals  are  among 
the  most  prized  of  all  furs,  as  will  be  noted  later.  One  of  the  most  im- 
portant uses  of  some  of  our  smaller  carnivora,  notably,  the  skunk,  mink, 
weasel,  fox,  coyote,  and  others,  is  in  the  destruction  of  many  of  our 
rodent  pests,  soon  to  be  described.  Most  of  the  animals  just  named  are 
considered  by  the  average  farmer  to  be  a  nuisance  because  of  the  oc- 
casional raids  that  may  be  made  on  his  inadequately  protected  poultry, 
but  a  few  farmers  are  beginning  to  realize  the  value  of  these  carnivora 


MAMMALIA 


223 


as  rodent  destroyers  and  are  taking  steps  to  protect  them.  Some 
farmers  insist  that  skunks  in  particular  should  be  protected  by  law 
against  skin  hunters,  on  account  of  their  value  to  agriculture. 

Pinnipedia.     Seals. — All    of    the    above    carnivorous    fur-bearers 
belong  to  the  terrestrial  group  of  carnivora.     Of  the  aquatic  forms  the 


FIG.   143. — The  beaver,    Castor  canadensis . 

in  Canada.} 


(From  Jones,  Fur    Farming 


fur-seal  is  the  most  important  and  is,  perhaps,  the  best  known  of  all  the 

fur-bearing  animals,  though  its  fur  is  so  often  and  so  closely  imitated 

that  most  people  cannot  distinguish  the  real  thing  from  its  imitations. 

The  fur-seal,  Callorhinus  alascanus,  Fig.  144,  has  not  only  been  an 


224  ECONOMIC  ZOOLOGY 

important  commercial  animal  but  it  has  been  a  subject  of  inter- 
national controversy,  as  will  be  noted  below. 

The  natural  history  of  the  fur-seal  is  interesting  and  must  be 
understood  before  the  economic  problems  involved  can  be  handled. 

The  home  of  the  Alaskan  fur-seal  (if  we  call  "home"  the  place  where 
it  breeds)  is  along  the  rocky  shores  of  the  Pribilof  and  other  islands  of 
the  Aleutian  group.  Here  large  herds  of  seals  assemble  for  the  short 
summer  season,  the  places  of  assemblage  being  known  as  "  rookeries. " 
The  males  are  known  as  " bulls"  and  are  enormously  larger  than 
the  females  or  "cows. "  The  young  are  known  as  "pups, "  so  that  the 
popular  nomenclature  is  decidedly  mixed.  The  bulls  arrive  at  the 
breeding  grounds  first,  from  the  south,  early  in  May;  the  height  of 
the  season  is  the  middle  of  July  and  the  southern  migration  begins  in  Au- 
gust. As  the  females  arrive  they  are  driven  or  carried  bodily  into  groups 
known  as  "harems."  A  harem  consists  of  from  one  to  a  hundred  or 
more  cows,  presided  over  by  a  single  old  bull ;  an  average  number  for  a 
harem  might  be  about  thirty.  The  bulls  fight  over  the  possession 
of  the  cows,  the  largest  and  the  fiercest  bulls  securing  the  largest  number 
of  cows.  In  these  perpetual  fights  not  only  are  the  skins  of  the  bulls 
torn  and  ruined,  but  the  cows  and  pups  are  often  injured  and  even 
killed.  The  young  bulls  that  are  not  large  and  strong  enough  to  secure 
a  harem  are  known  as  "bachelors,"  and  it  is  these  uninjured  and,  for 
breeding  purposes,  useless  bachelors  that  supply,  or  should  supply,  the 
skins  of  commerce. 

The  single  young  is  born-  soon  after  the  arrival  of  the  seals  and  the 
cow  is  then  served  by  the  bull.  Many  pups  are  killed  as  noted  above, 
many  die  of  starvation,  and  many  of  hookworm  and  other  diseases.  It 
is  probable  that  the  killing  of  the  extra  males,  say  95  out  of  every  100, 
would,  by  diminishing  the  fighting,  actually  increase  the  prolificness 
of  the  herd  by  diminishing  the  death-rate  of  the  pups  and  injury  to  the 
cows. 

The  seals  are  killed  with  clubs,  after  being  surrounded  by  a  group  of 
men  and  driven  to  a  flat  "killing  ground"  where  the  desirable  ones  are 
slaughtered  and  the  rest  are  allowed  to  return  to  the  sea.  At  the  close 
of  the  breeding  season  the  seals  start  on  their  southward  journey  for 
the  winter  which  may  extend  as  far  south  as  California.  It  was  during 
this  migration  that  the  most  destructive  killing  of  seals  by  man  took 
place,  beginning  about  1881-2.  This  so-called  "pelagic  sealing" 


MAMMALIA 


15 


226  ECONOMIC  ZOOLOGY 

came  near  exterminating  the  herd  and  causing  international  war.  The 
reasons  for  the  excessive  destructiveness  of  pelagic  sealing  were  as 
follows:  the  seals  were  killed  with  spears  or  guns  as  they  lay  sleeping 
at  the  surface  of  the  sea;  as  the  sex  of  the  animals  thus  killed  could 
not  be  determined  until  after  capture  the  females  as  well  as  the  young 
males  were  killed.  With  the  death  of  each  adult  female  not  only  was 
the  adult  killed,  but  her  unborn  young  and  her  sucking  pup  also 
perished,  making  at  least  three  deaths  for  each  hide  secured.  This, 
of  course,  could  not  long  continue  without  a  rapid  destruction  of  the 
herd  and  pelagic  sealing  was  stopped  barely  in  time  to  save  it. 

After  the  United  States  bought  Alaska  she  seized  and  confiscated 
all  vessels  caught  in  pelagic  sealing,  assuming  that  seals  that  bred 
on  our  coasts  were  ours  when  at  sea;  this  brought  on  a  serious  con- 
troversy with  England  that  lasted,  with  more  or  less  danger  and  bad 
feeling,  for  25  years  or  more,  until  the  convention  of  1911,  be- 
tween Great  Britain,  Russia,  Japan  and  the  United  States,  pro- 
hibited all  pelagic  killing  for  a  period  of  15  years.  Possibly  at  the 
expiration  of  this  period  the  time  may  be  extended  indefinitely. 
At  about  the  same  time  the  United  States  enacted  a  law  prohibiting 
even  land  killing  for  a  period  of  10  years.  This  law  has  caused  much 
criticism  by  those  familiar  with  the  breeding  habits  of  the  Alaskan 
seal,  as  briefly  described  above. 

The  agreement  to  suspend  pelagic  sealing  is  one  of  the  most  note- 
worthy attempts  to  save  a  vanishing  race  of  animals  by  international 
treaty  that  we  have.  The  diminution  of  the  fur-seal  catch  since  the 
early  eighties  are  shown  in  the  figures  from  the  offerings  of  furs  at 
the  London  Auction  sales  and  other  places;  for  example  in  1887, 
when  the  sales  were  greatest,  there  were  offered  (according  to  P.  R. 
Poland  &  Son,  London)  226,370;  in  1897  there  were  123,336;  and  in 
1907,  55,914;  since  the  last  date  they  have  fallen  still  lower.  According 
to  the  same  authority  the  catch  of  seals  in  Alaska  fell  from  122,166 
in  1886  to  13,584  in  1910,  when  killing  there  ceased. 

It  is  likely  that  but  for  the  prohibition  of  pelagic  sealing  the  Alaskan 
fur-seal  would  have  been  exterminated  as  was  the  American  Bison 
that,  a  generation  or  two  ago,  roamed  our  western  plains  in  herds  of 
enormous  size  and  was  almost  completely  destroyed  by  thoughtless 
and  useless  hunting. 


MAMMALIA 

The  price  of  seal-skins  has  varied  with  the  year  and  the  character 
of  the  skins,  ranging  from  about  $8  to  $40  each. 

The  treatment  of  the  seal-skin  before  it  is  ready  to  be  made  into 
garments  is  rather  an  extended  process  and,  of  course,  adds  to  the  cost 
of  the  finished  article. 

Rodentia  (Glires).  Gnawing  Animals. — This  is  a  large  group  of 
small  animals,  whose  chief  characteristic  is  the  possession  of  sharp, 
chisel-like  incisor  teeth,  which  are  particularly  well  adapted  to  gnawing. 
There  are  never  more  than  two  incisors  in  the  lower  jaw  and  usually 
only  two  in  the  upper  jaw.  The  incisors  and  sometimes  the  back  teeth 
have  persistent  pulps  which  causes  them  to  continue  to  grow,  to  make 


PIG.  145. — Photograph  of  skull  of  woodchuck,  showing  an  upper  incisor  that 
had  grown  in  an  arc  of  a  circle  until  it  entered  the  roof  of  the  mouth,  after  its  oppos- 
ing lower  incisor  had  been  broken  off.  X  i . 

up  for  the  wearing  away  of  their  cutting  surfaces.  If  an  incisor  be 
broken  off,  the  opposite  tooth,  having  no  mate  to  wear  against  :will 
continue  to  grow,  in  the  arc  of  a  circle,  until  it  may  cause  the  death 
of  its  possessor,  Fig.  145.  No  canine  teeth  are  present,  which  leaves 
a  wide  space  between  the  incisors  and  the  premolars.  While  rodents, 
as  a  class,  are  vegetable  feeders,  some  forms,  such  as  the  common  rats 
and  mice,  are  practically  omnivorous.  The  integument  is  usually  furry, 
sometimes  hairy  and  occasionally  spiny  (Porcupines);  the  digits  end 
in  claws;  the  cecum  is  very  large;  the  cerebral  hemispheres  are  com- 
paratively smooth. 

This   extensive   order   of   more   than    1400   species    includes    the 
following   well-known   North   American  families:   Muridae,  the  rats 


228  ECONOMIC  ZOOLOGY 

and  mice;  Sciuridae,  the  squirrels;  Leporidae,  the  rabbits  and  hares, 
Castoridae,  the  beavers;  Geomyidae,  the  pocket  gophers;  and  Ccendidae 
(Hystricidae)  the  porcupines. 

This  largest  of  the  orders  of  mammals  is  also  one  of  the  most  im- 
portant, economically,  since  it  is  one  of  the  most  destructive  of  all 
the  animal  groups.  It  is  the  negative  importance,  then,  that  will 
be  chiefly  considered  here,  though  some  of  the  species  have  some  posi- 
tive value  to  man,  as  already  noted  in  connection  with  the  fur- 
bearing  animals. 

Murida.  Rats  and  Mice. — The  largest  of  the  above  -mentioned  fami- 
lies of  rodents,  both  as  to  numbers  of  species  and  of  individuals,  and  by 
far  the  most  important  economically  is  the  family  Murida.  Of  the 
Muridae  the  most  important  genus  is  Rattus,  including  the  only  too 
familiar  rats,  whose  damage  to  man  each  year  in  the  United  States 
has  recently  been  estimated  by  the  Biological  Survey  to  be  at  least  $200,- 
000,000,  or  the  value  of  the  labor  of  an  army  of  200,000  men.  Not 
only  does  the  rat  cause  this  enormous  monetary  loss,  but  it  is  the 
known  disseminator  of  the  bubonic  plague  and  some  less  serious  diseases, 
and  is  supposed  to  be  the  carrier  of  several  others;  so  that  a  prominent 
medical  man  recently  stated  that  he  considered  the  rat  the  worst  dis- 
ease carrier  we  know. 

The  plague  was  known  long  before  the  beginning  of  the  Christian 
Era,  and  on  several  occasions,  in  Europe,  under  the  name  of  the  "  black 
death"  it  carried  off  people  by  the  millions.  In  1907  the  deaths  from 
plague  in  India  were  estimated  at  2,000,000.  Since  rats,  as  is  well 
known,  are  common  on  board  of  ships,  it  is  very  easy  to  see  how  the  plague 
has  been  carried  from  infected  ports  to  all  parts  of  the  world.  When  it 
became  known  that  the  plague  is  a  disease  of  rats,  carried,  on  the  death 
of  the  rat,  to  man  by  the  rat  flea,  the  problem  of  plague  control  resolved 
itself  into  the  problem  of  rat  extermination.  How  well  this  may  be 
done  by  a  vigorous,  cooperative  effort  is  illustrated  by  the  successful 
campaign  waged,  some  years  ago  in  San  Francisco  and  surrounding  cities. 
Incidentally  the  problem  was  complicated  there  by  the  discovery  that 
the  rat  fleas  were  also  carried  by  the  ground  squirrels,  so  widely  dis- 
tributed in  that  part  of  the  country.  The  methods  of  extermination 
of  both  rats  and  squirrels  will  be  discussed  later. 

Three  kinds  of  rats  are  found  in  the  United  States  and  are  gener- 
ally distributed  throughout  most  parts  of  the  civilized  world.  Their 


MAMMALIA  2  29 

scientific  names  have  been  frequently  changed;  those  given  here  are 
the  ones  used  in  the  Biological  Survey  of  the  United  States  Department 
of  Agriculture. 

The  common  rat  of  most  parts  of  the  country  is  the  brown  or  Nor- 
way rat,  Rattus  norvegicus,  also  known  as  the  wharf  rat,  the  sewer  rat, 
the  grey  rat,  the  house  rat,  etc.,  Fig.  146.  Less  common  are  the  black 
rat,  Rattus  rattus  rattus,  and  the  roof  rat,  Rattus  rattus  alexandrinus. 
The  latter  two  are  somewhat  smaller  than  the  former,  have  longer  ears 
and  tail  and  are  not  so  vigorous  and  aggressive,  so  that  they  usually  give 
way  before  the  brown  species;  they  are  similar  in  size  and  form  but  are 
distinguished  from  each  other  by  the  difference  in  color,  the  roof  rat  re- 
sembling more  the  brown  rat  in  color  while  the  black  rat  is  much  darker, 
nearly  black.  The  roof  rat  is  common  in  some  parts  of  the  south. 


PIG.   146. — Brown  or  Norway  rat,  Rattus  norvegicus.      X/4-     (From  Lantz,  House 

Rats  and  Mice.) 

Key  to  Specie's  of  House  Rats  and  Mice.     (Lantz) 

Size,  small.     Total  length  of  adult  less  than  200  millimeters ....  M us  musculus. 
Size,  large.     Total  length  of  adult  over  300  millimeters. 

Ears  moderate,  when  laid  forward  barely  or  not  reaching  eye;  tail  shorter 
than  (rarely  equal  to)  the  length  of  head  and  body,  darker  above  than 
below;  color  of  body  normally  grey-brown  above,  whitish  below:  hind  foot 

38-46  millimeters  (Brown  Rat) Rattus     norvegicus. 

Ears  larger,  when  laid  forward  reaching  at  least  to  middle  of  eye;  tail  longer 
than  head  and  body,  dusky  all  around;  hind  foot  33-37  millimeters.  Color 

blue  black  above,  slaty  below  (Black  Rat) Rattus  rattus  rattus. 

Color  graying  brown  above,  white  or  yellowing  white  below  (Roof  Rat). 

Rattus  rattus  alexandrinus. 


230  ECONOMIC   ZOOLOGY 

In  habits  the  three  rats  are  so  similar  that  the  following  description 
will  apply  to  all.  The  common  white  rats,  familiar  as  pets  and  as 
subjects  for  scientific  investigation,  are  merely  albinos,  probably  of  the 
Norway  rat.  They  are  usually  mild  and  gentle  in  disposition  and  are 
not  often  seen  in  the  wild  state.  The  original  home  of  the  rat  was  prob- 
ably India  or  some  other  part  of  the  Orient;  it  suddenly  appeared  in  Eu- 
rope in  1727  and  about  1775  it  was  introduced  into  America.  There 
are  now  only  two  or  three  States  in  which  it  is  not  known.  The 
average  weight  of  the  brown  rat  is  from  i  to  ij^  pounds  and  an 
animal  of  that  size  that  occurs  in  such  enormous  numbers  can  destroy 
an  immense  amount  of  valuable  property.  As  has  been  said  the  rat 
is  perfectly  omnivorous  in  habits;  though  it  may  prefer  certain  kinds 
of  food,  it  will  when  hungry  eat  anything  that  can  be  chewed,  and  it 
frequently  spoils  more  than  it  actually  eats. 

On  the  farm  they  are  often  a  terrible  pest.  They  eat  corn  when 
newly  planted,  necessitating  replanting;  they  eat  it  from  the  stalk, 
for  rats  are  excellent  climbers  and  are  able  to  perform  astonishing  feats 
of  this  kind;  they  nest  under  the  corn  shocks  and  feed  on  the  corn  all 
winter,  in  sections  where  corn  is  left  out  all  winter  for  cattle  feeding; 
they  eat  corn  and  all  other  grains  in  the  bin  and  grainery,  unless  the 
latter  are  thoroughly  rat-proofed.  The  manager  of  a  large  cattle  ranch 
in  Southwestern  Virginia  estimated  his  loss  of  corn  in  the  shock  at 
500  bushels  in  a  single  season  from  rats;  and  many  farmers  estimate 
their  annual  loss  of  corn  in  the  crib  at  from  10  per  cent,  to  25  per  cent. 
After  the  grain  reaches  the  mill  it  is  seriously  injured  by  rats  and  mice 
unless  very  active  preventive  measures  be  adopted. 

Poultry  is  so  seriously  affected  that  in  some  instances  farmers  have 
given  up  the  attempt  to  raise  it;  chickens  nearly  ready  for  market 
are  killed  and  carried  away  by  rats,  the  damage  being  often  wrongly 
ascribed  to  skunks,  minks  and  other  wild  animals.  Nesting  birds, 
as  noted  in  the  chapter  on  birds,  are  also  seriously  injured  in  some  places. 

Fruits  and  vegetables,  especially  while  in  transit  to  market  on  trains 
or  vessels,  are  often  very  seriously  damaged.  Many  instances  are  re- 
ported of  serious  damage  to  meat  in  the  farmer's  smoke  house,  and  cases 
are  reported  of  young  hogs  being  killed  and  eaten  by  rats.  Besides 
the  above,  the  damage  on  the  farm,  by  rats  in  undermining  and  in 
otherwise  injuring  buildings,  walls,  etc.,  is  often'considerable. 

In  towns  and  cities  the  loss  is  equally  great  and  is  probably  more 


MAMMALIA  231 

varied;  here  their  favorite  haunts  are  markets,  restaurants  and  other 
places  where  food  is  stored,  especially  in  the  neighborhood  of  docks 
and  wharves.  A  large  milling  company  of  Kentucky  estimated  its 
annual  loss  upon  grain  sacks  alone  at  $3000  and  in  smaller  mills 
it  is  common  to  hear  the  manager  estimate  his  annual  loss  at  many 
hundreds  of  dollars. 

"In  1898  a  large  packing  house  in  Chicago  had  3360  hams  de- 
stroyed by  rats;"  and  in  the  smaller  branch  offices  of  the  packing  houses, 
where  thorough  rat  proofing  has  not  been  adopted,  heavy  losses  to 
meat  are  reported. 

Commission  merchants  suffer  heavily  from  rats,  which  eat  all  kinds 
of  goods  and  carry  off  eggs  by  the  dozen  in  a  single  night. 

The  department  stores,  especially  those  that  handle  food-stuffs, 
as  most  of  them  do,  suffer  so  heavily  that  most  of  them  regularly  em- 
ploy, by  the  year,  professional  rodent  exterminators  that  they  pay  often 
as  much  as  $50  or  more  a  month.  Besides  eating  and  spoiling 
large  quantities  of  food-stuffs  the  rat  does  heavy  damage  in  various  other 
ways;  for  example,  numerous  fires  have  been  started  from  rats  and  mice 
gnawing  matches;  buildings  have  been  flooded  by  rats  gnawing  through 
lead  water-pipes;  expensive  china  and  glassware  are  sometimes  knocked 
from  shelves  and  broken;  bedding,  furniture,  drygoods  and  other  in- 
edible materials  are  often  destroyed  or  rendered  unsalable. 

Few  people  realize  the  numbers  of  rats  that  are  sometimes  found 
in  infested  regions.  After  careful  and  conservative  investigation  it  has 
been  estimated  that  in  towns  the  normal  rat  population  is  about  equal 
to  the  human,  while  in  rural  districts  it  is  much  greater.  On  a  rice 
plantation  of  400  acres  over  17,000  rats  were  killed  in  a  single  year. 
In  a  single  raid  in  a  city  warehouse  often  bushels  of  rats  are  destroyed. 
1700  rats  have  been  destroyed  in  fumigating  a  steamship. 

Under  certain  conditions  rats  have  been  known  to  migrate  in  great 
hordes,  like  their  relatives,  the  lemmings;  and  there  is  a  more  or  less 
definite  periodic  migration  from  their  warm  winter  quarters  in  towns 
and  buildings  to  the  adjoining  fields,  and  back  again,  with  the  change  of 
seasons. 

Being  secretive  and  largely  nocturnal  in  habits  there  are  often  many 
more  rats  about  a  certain  region  than  is  generally  appreciated,  and  this, 
added  to  their  remarkable  cunning,  enables  them  to  multiply  with  as- 
tonishing rapidity. 


232 


ECONOMIC  ZOOLOGY 


A  rat  may  bring  forth  from  three  to  a  dozen  litters  of  young  a  year, 
with  from  six  to  twenty  in  a  litter,  averaging  perhaps  ten  per  litter. 
At  this  rate,  and  with  the  females  reaching  sexual  maturity  in  three  or 


four  months,  it  will  be  seen  how,  under  favorable  conditions,  a  locality 
may,  in  a  short  time,  be  simply  overwhelmed  with  the  pests,  so  that  the 
most  vigorous  remedial  efforts  must  be  exerted  to  stem  the  tide. 


MAMMALIA 


233 


The  traps,  poisons  and  other  methods  of  destroying  rats  are  number- 
less, and  many  of  them  are  very  effective;  but  here,  as  in  other  things, 
"an  ounce  of  prevention  is  worth  a  pound  of  cure,"  and  it  is  far  better 


to  prevent  the  breeding  of  rats  or  to  keep  them  out  of  mischief  than  it  is 
to  destroy  them  after  they  have  begun  to  be  a  serious  menace. 

There  are  at  least  two  good  reasons  for  protecting  food  from  rats: 


234 


ECONOMIC  ZOOLOGY 


obviously  to  save  the  food,  but  also  for  the  reason  that  well-fed  rats 
breed  much  faster  than  those  with  a  scant  food  supply.  There  are 
several  ways  to  starve  out  the  rat:  one  is  to  keep  all  garbage  and  other 


Si 


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Si 

o  J2 


O    o3      - 

eli 


such  refuse  in  rat-proof  metal  cans,  Fig.  147;  another  is  to  protect 
buildings  and  other  receptacles  for Jood-stuffs  against  the  rat.     In  con- 


MAMMALIA  235 

structing  a  new  building  it  is  comparatively  easy  and  inexpensive  to 
make  it  rat-  or  even  mouse-proof,  and  in  many  cities  this  is  enforced 
by  law;  in  the  case  of  an  old  building  it  is  often  difficult  but  seldom  im- 
possible to  properly  rat-proof.  In  many  barns  and  stables  where  the 
expense  of  rat-proofing  the  entire  building  would  be  prohibitive  it  is 
easy  to  completely  cover  the  feed  or  grain  bins  with  wire  netting;  or 
to  pile  the  bales  of  hay  or  sacks  of  feed  on  elevated  platforms,  either 
supported  from  the  floor  as  in  Fig.  148  or  hung  from  a  ceiling  that 
has  no  rafters  along  which  rats  can  run.  An  arrangement  such  as 
shown  in  Fig.  148  not  only  protects  the  material  but  also  removes 
the  harbor  in  which  the  rats  hide  and  rear  their  young,  one  of  the 
most  important  of  the  preventive  measures  of  rat  extermination. 

In  rat-proofing  a  judicious  use  of  concrete  and  galvanized  wire  net- 
ting will  do  the  work,  but  both  are  usually  necessary.  Many  houses 
are  made  with  rat-proof  cellars,  but  if  the  cellar  windows  are  not  screened 
rats  and  mice  will  soon  "make  their  entrance  and  the  concrete  walls 
and  floors  have  been  in  vain,  so  far  as  rodent  infestation  is  concerned. 
At  a  very  slight  expense  the  windows  and  doors  can  be  closed  with  wire 
netting  of  about  %  inch  mesh.  Another  frequent  point  of  entry  into 
otherwise  rat-proof  buildings  is  through  or  around  drain  or  other  pipes. 
The  openings  around  all  pipes  should  be  tightly  closed  with  a  mass  of 
cement  as  thick  as  the  wall.  The  lower  edge  of  all  outer  wooden  doors 
should  be  covered  with  a  strip  of  tin  or  other  metal  about  a  foot  high  to 
prevent  rats  from  gnawing  through. 

A  frame  building  with  brick  or  stone  foundation,  may  be  made  rat- 
proof  by  cementing  the  entire  floor  of  the  cellar,  screening  the  windows 
and  filling  in  the  space  between  the  laths  and  outer  boards  with  concrete 
to  a  height  of  about  a  foot.  Or,  a  cement  wall,  starting  a  couple  of  feet 
under  ground  and  extending  a  foot  above  ground  may  be  built  around 
the  outside  wall  of  the  house,  as  shown  in  Fig.  149.  Porches  and  small 
buildings  without  cellars  should  be  elevated  a  foot  or  more  above  the 
ground  to  prevent  the  harboring  of  rats  and  to  allow  dogs  and  other 
rat  destroyers  to  enter.  Floors  and  wooden  walks  whose  timbers  are 
laid  directly  on  the  ground  are  sure  to  harbor  rats.  In  stables  where 
cement  floors  are  objectionable,  wooded  floors  may  be  laid  directly 
on  the  cement.  Various  methods  of  proofing  corn  cribs  may  be  em- 
ployed. One  method  is  shown  in  Fig.  150,  where  is  built  a  concrete 
wall,  sunk  about  2Q  inches  in  the  ground?  with  a  concrete  floor,  upon 


236 


ECONOMIC  ZOOLOGY 


which  the  house  is  constructed.  The  lower  part  of  the  slats  are  cov- 
ered with  wire  netting,  at  the  top  of  which  is  a  belt  of  metal,  about  a 
foot  wide,  to  keep  the  rodents  from  climbing  over  the  netting. 


A  cheaper  method  is  to  cover  the  entire  floor,  beneath  the  boards, 
with  netting,  with  the  same  belt  of  metal  and  netting  around  the  sides, 


MAMMALIA 


237 


A  common  method  is  to  build  the  house  on  tall  posts  that  are  either 
belted  with  metal  or  have  a  large  inverted  pan  at  the  top  of  each  post; 
to  be  effective  the  floor  should,  in  this  case,  be  at  least  3  feet  from 
the  ground.  In  any  case  it  is  obviously  important  never  to  leave  the 
door  of  the  crib  open  and  never  to  lean  lumber  or  farm  implements 
against  the  walls  by  means  of  which  rats  may  climb  over  the  screening. 
Some  farmers  prefer  to  completely  cover  the  crib  with  wire  netting, 
others  to  make  the  wall  entirely  of  concrete,  except  openings  for  ventila- 
tion. Probably  no  farmer  who  has  once  had  a  rodent-proof  corn  crib 
ever  cares  to  be  without  this  means  of  protecting  his  corn.  In  some 


i 


PIG.  150. — Perspective  of  rat-proof  corn  crib,  showing  concrete  foundation  by 
dotted  lines;  also  the  belt  of  metal  to  keep  rats  from  climbing  up  the  sides.  (From 
Lantz,  House  Rats  and  Mice.) 

cases  the  cost  of  proofing  will  be  saved  in  a  single  year.  On  almost 
every  farm  there  are  old  out-houses,  piles  of  lumber  and  trash,  and 
many  other  places  that  furnish  harbors  for  rats;  these  should  be 
destroyed  or  cleaned  up. 

For  those  who  rent  houses  that  are  not  rat-proof  there  are  number- 
less schemes  for  protecting  edible  goods  from  rats  and  mice,  largely  by 
the  use  of  tin  and  screens  and  by  elevation  above  the  floor.  Entire 
rooms  are  often  lined  with  wire  netting  as  a  place  to  store  easily  dam- 
aged goods.  Foods  preserved  in  tin  and  glass  are,  of  course,  safe  from 
rodents. 

While,  as  has  been  said,  it  is  much  better  to  keep  rats  away  from 


238  ECONOMIC  ZOOLOGY 

food  and  not  allow  them  breeding  places,  it  is  not  possible  always  to 
do  this,  and  it  is  usually  necessary  to  combine  these  preventive  meas- 
ures, with  active  measures  for  their  destruction. 

Two  chief  destructive  agents  are  used  (besides  cats,  dogs,  etc.,  to 
be  noted  later):  traps  and  poisons.  There  are  numerous  types  of 
traps  on  the  market,  many  of  which  are  effective  if  intelligently  handled. 
Perhaps  the  best  traps  for  general  purposes  are  the  spring  or  guillotine 
traps;  some  of  these  are  made  entirely  of  metal,  Fig.  151,  and  are  easily 


FIG.   151. — All  metal  guillotine  or  "snap"  rat   trap.      X/^.     (From  Lantz,   House 

Rats  and  Mice.) 

deodorized  by  heat  or  water;  others  have  a  wooden  base,  Fig.  152,  and 
have  the  advantages  of  being  somewhat  cheaper  and  of  being  more 
easily  set.  These  traps  kill  the  victim  instantly  and  are  so  cheap  that 
they  may  be  set  by  the  dozen,  which  is  obviously  advantageous.  They 
can  also  be  placed  in  the  runways  of  the  rats  where  they  often  catch 
rats  without  being  baited.  They  are  very  "quick  on  the  trigger" 
and  it  is  almost  impossible  for  a  rat  to  remove  the  bait.  Various  sub- 
stances should  be  tried  for  bait,  usually  some  kind  of  food  that  is  scarce 
in  the  place  where  the  trap  is  set;  for  example,  where  grain  is  about, 


MAMMALIA 


239 


bait  with  meat,  in  a  meat-shop  bait  with  grain.  Vienna  sausage, 
toasted  bacon,  toasted  cheese,  raw  meat,  fish,  apple,  vegetables,  oat- 
meal, etc.,  may  be  tried;  if  one  substance  does  not  tempt  the  rats,  try 
others.  Put  the  traps  in  runways  and  hidden  places.  It  may  be  well 


PIG.   152. — Guillotine  or  "snap"  rat  and  mouse  traps  with  wooden  bases. 

to  wash  the  traps  and  handle  them  with  gloves  to  keep  them  from 
smelling  of  the  human  hands. 

Another  type  of  trap  is  the  wire  cage  trap,  Fig.  153,  which  has  the 
advantage  of  catching  under  favorable  conditions,  a  number,  perhaps  a 


FIG.   153. — Wire  rat  trap.       xK- 

couple  of  dozen,  rats  at  one  time.  Such  a  trap  should  be  partially 
covered  with  boards  or  sacking  and  should  be  baited  with  some  form  of 
bait  such  as  was  mentioned  above.  It  is  often  well  to  leave  the  trap 
open,  for  a  few  nights,  to  get  the  rats  accustomed  to  going  in  and  out  of 


240 


ECONOMIC  ZOOLOGY 


it.  Sometimes  good  results  can  be  secured  by  the  use  of  some  form  of 
barrel  trap.  Fig.  154,  i,  shows  a  barrel  with  a  head  of  heavy  paper  tied 
over  the  open  end;  on  this  paper  food  is  placed  for  several  nights  till 
the  rats  get  the  habit  of  going  there  for  it,  then  a  couple  of  slits  are  cut 
in  the  paper,  which  allows  the  rats  to  fall  into  the  barrel.  A  nicely  bal- 
anced hinged  lid  may  be  used,  as  shown  in  Fig.  154,  2.  If  a  foot  of 
water  be  placed  in  the  barrel  the  rats  will  be  drowned  by  morning, 
which  will  save  the  unpleasant  task  of  killing  them.  Various  modifi- 
cations of  this  trap  may  be  used. 

By  the  use  of  a  small  movable  wire  or  wooden  pen  that  may  be  put 
around  shocks  or  piles  of  corn  or  other  grain  so  that  the  grain  may  be 


PIG.  154. — Barrel  rat  traps,  i,  with  bait  fastened  to  stiff  paper  cut  across.  2, 
with  the  bait  fastened  to  a  hinged  lid  that  can  dip  only  one  way  because  of  a  nail  at 
a.  (After  Lantz,  House  Rats  and  Mice.) 

thrown  out  of  the  pen,  the  hidden  rats  are  kept  inclosed  and  can  be 
easily  killed  by  dogs  or  with  clubs. 

For  destroying  rats  out  of  doors  or  in  barns,  stables  and  other  houses 
where  the  odor  of  dead  animals  is  not  a  serious  objection,  the  use  of 
poisons  is  often  the  most  effective  method.  In  some  States  the  law 
requires  that  notice  be  given  before  poisons  are  used,  and  in  all  cases 
extreme  care  should  be  taken  not  only  to  keep  the  poison  out  of  the  reach 
of  children  and  other  persons,  but  also  to  protect  dogs  and  other  do- 
mestic animals.  Various  poisons  are  in  more  or  less  common  use, 
besides  the  numerous  special  preparations  that  are  sold  in  packages 
for  this  purpose.  Some  of  these  preparations  seem  very  effective, 
others  are  more  or  less  useless. 


MAMMALIA  241 

Probably  the  most  commonly  used  poison  is  powdered  white  ar- 
senic which  is  cheap  but  is  not  so  effective  as  some  of  the  others.  It 
is  used  in  various  ways,  the  easiest  being  to  rub  it  into  fresh  fish  or  meat, 
spread  it  upon  buttered  bread,  or  make  it  into  a  dough  with  corn- 
meal  and  white  of  eggs  (i  part  by  weight  of  arsenic  to  about  12 
of  cornmeal). 

A  better  poison  is  barium  carbonate,  which  may  be  used  in  about 
the  same  way  as  the  arsenic,  except  that  a  larger  proportion  (i  to  4) 
of  the  poison  is  used  in  making  the  dough.  Its  action  is  so  slow  that 
rats  often  escape  from  buildings  before  death,  so  that  it  may  sometimes 
be  safely  used  in  dwellings.  In  the  small  quantities  used  for  rats  it 
is  not  usually  fatal  to  domestic  animals. 

Strychnin  (usually  as  the  sulphate)  is  one  of  the  best  poisons  for 
rats  but  it  is  so  violently  poisonous  that  it  should  be  used  with  extreme 
care.  Tiny  pieces  may  be  inserted  in  small  pieces  of  meat,  or  oatmeal 
or  other  grain  may  be  soaked  over  night  with  strychnin  syrup,  made 
by  dissolving  half  an  ounce  of  the  sulphate  in  a  pint  of  boiling  water  and 
stirring  in  a  pint  of  thick  sugar  syrup. 

Phosphorus  is  used  very  commonly  as  a  rat  poison,  but  owing  to 
the  fact  that  fires  have  frequency  been  caused  by  its  use  it  is  not  to  be 
recommended.  It  is  often  claimed  that  certain  of  the  phosphorus 
poisons  " embalm"  or  dry  up  the  bodies  of  rats  so  that  they  have  no 
odor — this  statement  is  not  true  of  phosphorus  nor  probably  of  any 
other  known  poison. 

In  laying  poisons  for  rodents  it  is  important  that  they  be  placed 
well  down  in  the  burrows  or  be  hidden  so  that  domestic  animals  may  not 
get  at  them;  this  is  particularly  true  about  stables,  chicken  houses  and 
such  places.  A  very  good  way  to  lay  poison,  so  that  chickens  and 
other  animals  cannot  eat  it,  is  to  put  the  poisoned  food  in  a  small, 
upturned  box  and  invert  a  larger  box,  in  the  sides  of  which  small  holes 
have  been  cut,  over  the  smaller  one. 

For  killing  rats  in  ships  and  sometimes  in  storehouses  and  other 
places  fumigation  is  often  very  effective.  In  such  places  sulphur 
dioxid,  chlorine,  carbon  monoxid  and  hydrocyanic  acid  are  the  gases 
most  frequently  used.  Chlorine  because  of  its  bleaching  properties, 
carbon  monoxid  because  of  its  lack  of  odor,  and  hydrocyanic  acid 
because  of  its  extreme  danger  to  human  life  are  all  objectionable;  so  that 
sulphur  dioxid  is  perhaps  to  be  most  recommended,  though  it  has  some 

16 


242 


ECONOMIC  ZOOLOGY 


bleaching  properties.     By  means  of  special  furnaces  it  is  now  forced 
into  the  compartments  of  vessels  as  they  lie  at  the  dock  and  the  whole 


process  takes  less  than  half  a  day  and  costs  a  comparatively  insignificant 
sum  compared  to  the  benefits  derived.  At  many  sea-ports,  especially 
during  times  of  plague,  all  vessels,  or  at  least  all  those  from  tropical 


MAMMALIA  243 

or  infected  ports,  must  be  fumigated  either  at  the  end  of  each  voyage 
or  at  certain  intervals.  At  most  ports,  also,  the  law  requires  certain 
or  all  vessels  to  guard  all  lines  leading  to  shore  with  metal  rat-shields, 
Fig.  155,  to  prevent  rats  from  leaving  or  entering  the  vessels.  While 
rats  are  excellent  swimmers  they  are  not  apt  to  deliberately  jump  into 
the  water  and  swim  ashore. 

For  killing  rats  in  their  burrows  in  fields,  along  streams,  etc.,  carbon 
disulphid  is  often  very  effective.  A  wad  of  cotton  or  any  other  ab- 
sorbent substance  is  saturated  and  dropped  into  the  hole,  which  is 
then  closed  with  dirt  to  prevent  the  escape  of  the  gas;  the  rats  are  left 
buried  in  the  ground. 

Various  so-called  rat  viruses  are  on  the  market  that  are  supposed  to 
cause  contagious  bacterial  diseases  among  rats.  The  idea  is  excellent 
but  so  far  none  of  these  viruses,  according  to  the  Biological  Survey, 
has  proved  satisfactory. 

A  number  of  domestic  animals  are  commonly  used  to  destroy  rats, 
the  domestic  cat  being  the  most  familiar.  While  an  occasional  cat  is 
found  that  is  a  veritable  terror  to  rats,  and  many  produce  dealers  and 
others  claim  great  efficiency  for  their  cats,  yet  their  value  as  ratters  is 
probably  greatly  exaggerated;  a  well- trained  fox  terrier  or  some  other 
breed  of  dog  is  usually  worth  many  cats,  as  a  destroyer  of  rats.  Ferrets 
were  formerly  much  used,  especially  in  connection  with  dogs,  to  rid 
houses  of  rats,  but  they  require  experienced  handling  and  are  not  so 
commonly  used  as  formerly. 

The  natural  enemies  of  rats  will  be  discussed  in  connection  with 
mice,  upon  which  they  feed  even  more  than  upon  rats.  As  has  been 
said  some  of  these  wild  animals  are  often  blamed  for  the  destruction 
of  poultry  really  due  to  rats. 

In  order  that  any  campaign  against  rats  may  be  effective  coopera- 
tion among  the  members  of  a  community  must  be  had.  If  one  person 
wage  war  upon  rats  on  his  property  they  will  swarm  over  to  the  neigh- 
boring properties  and  the  only  way  to  get  extensive  results  is  to  make 
the  campaign  a  community  affair  and  continue  it  from  year  to  year. 
By  interesting  women's  and  farmer's  clubs,  boards  of  trade  and  other 
civic  societies  much  may  be  accomplished.  By  having  the  town, 
county  or  state  place  a  bounty  of  a  few  cents  a  head  (or  tail)  upon  rats 
the  interest  of  the  small  boy  may  be  attracted;  and  if,  in  addition,  a 
cash  prize  for  the  greatest  number  of  rats  brought  in  during  a  certain 


244  ECONOMIC   ZOOLOGY 

period  be  offered  a  much  greater  activity  will  probably  be  secured  from 
both  individuals  and  from  clubs  and  societies  organized  for  the  specific 
purpose  of  waging  war  upon  this,  our  most  destructive  pest. 

Lantz  (170)  gives  the  following  summary  of  the  measures  needed 
for  combating  the  rat  and  mouse  nuisance: 

"i.  The  requirement  that  all  new  buildings  erected  shall  be  made  rat- 
proof  under  competent  inspection. 

"2.  That  all  existing  rat-proof  buildings  shall  be  closed  against  rats  and 
mice  by  having  all  openings  accessible  to  the  animals,  from  foundation  to 
roof,  closed  or  screened  by  door,  window,  grating,  or  meshed  wire  netting. 

"3.  That  all  buildings  not  of  rat-proof  construction  shall  be  made  so  by 
remodeling,  by  the  use  of  materials  that  may  not  be  pierced  by  rats,  or  by 
elevation. 

"4.  The  protection  of  our  native  hawks,  owls,  and  smaller  predatory 
mammals — the  natural  enemies  of  rats. 

"5.  Greater  cleanliness  about  markets,  grocery  stores,  warehouses, 
courts,  alleys,  stables,  and  vacant  lots  in  cities  and  villages,  and  like  care  on 
farms  and  suburban  premises.  This  includes  the  storage  of  waste  and 
garbage  in  tightly  covered  vessels  and  the  prompt  disposal  of  it  each  day. 

"6.  Care  in  the  construction  of  drains  and  sewers,  so  as  not  to  provide 
entrance  and  retreat  for  rats.  Old  brick  sewers  in  cities  should  be  replaced 
by  concrete  or  tile. 

"7.  The  early  threshing  and  marketing  of  grains  on  farms,  so  that  stacks 
and  mows  shall  not  furnish  harborage  and  food  for  rats. 

"8.  Removal  of  outlying  straw  stacks  and  piles  of  trash  or  lumber  that 
harbor  rats  in  fields  and  vacant  lots. 

"9.  The  keeping  of  provisions,  seed  grain,  and  food-stuffs  in  rat-proof 
containers. 

"10.  Keeping  effective  rat  dogs,  especially  on  farms  and  in  city  ware- 
houses. 

"  ii.  The  systematic  destruction  of  rats,  whenever  and  wherever  possible, 
by  (a)  trapping,  (6)  poisoning,  and  (c)  organized  hunts. 

"  12.  The  organization  of  clubs  and  other  societies  for  systematic  warfare 
against  rats." 

Mice. — Closely  related  to  the  rats  and  associated  with  them  in  the 
minds  of  all  as  plagues  of  mankind,  are  the  various  species  of  mice 
of  which  two  or  three  will  be  noted  here.  The  most  familiar  of  these 
is  the  common  house  mouse,  Mus  musculus,  a  pest  not  only  about 
houses  and  barns  but  also  in  the  fields.  Like  the  rats,  this  mouse  is 


MAMMALIA  245 

an  introduced  species  from  Europe.  It  is  somewhat  similar  to  the  rats 
in  habits  and  owing  to  its  small  size  it  is  able  to  escape  from  its  larger 
cousins  by  entering  crevices  too  small  for  the  rats  to  follow.  Although 
of  so  small  a  size  it  occasionally  occurs  in  such  incredible  numbers 
that  it  does  very  serious  damage,  as  was  recently  the  case  in  Australia 
where,  in  the  summer  of  1917,  enormous  quantities  of  wheat  were  de- 
stroyed by  mice,  which  suddenly  appeared  and  increased  with  unbeliev- 
able rapidity  until  they  swarmed  about  the  wheat  depots  by  the 
million. 

Owing  to  inadequate  shipping  facilities,  the  wheat  sacks  were 
collected  in  enormous  piles  at  various  places,  and  it  was  in  this  sacked 
wheat  that  the  mice  collected  and  did  such  serious  damage.  Photo- 
graphs were  shown  where,  by  gnawing  the  bottom  sacks,  the  whole 
pile  was  caused  to  collapse  into  a  mass  of  torn  bags  and  loose  grain; 
in  one  case  more  than  6000  sacks  of  wheat  were  "Reduced  to  a 
Sickening  Dump  Heap  by  a  Voracious  Host." 

After  trying  unsuccessfully  various  expedients  a  very  simple  remedy 
was  worked  out  as  follows:  the  stacks  of  bags  were  surrounded  by  a 
double  wall  made  of  strips  of  corrugated  iron  about  2  feet  wide. 
This  wall  made  a  series  of  narrow,  converging  runways,  whose  narrow, 
open  ends  opened  over  deep  pits.  By  hanging  empty  sacks  over  the 
outer  side  of  the  outer  wall  and  the  inner  side  of  the  inner  wall  the 
mice  were  enabled  to  get  into  the  runways  in  either  going  to  or  away 
from  the  stack,  but  they  could  not  escape  from  between  the  two  strips 
of  iron  and  were  easily  driven  through  the  narrow  end  of  the  passage 
into  the  pit,  where  they  were  killed  by  asphyxiating  gases.  By  this  sim- 
ple scheme  the  pest  was  brought  under  control.  Mice  were  caught, 
literally  by  the  ton  and  by  the  million.  For  example  it  was  reported 
that  approximately  500,000  mice,  weighing  about  8  tons,  were  captured 
in  four  nights  at  one  grain  store.  A  modification  of  this  method  might 
be  used  in  this  country  where  mice  become  particularly  abundant. 

Under  ordinary  conditions,  in  houses  and  stores,  the  house  mouse 
can  be  exterminated  by  the  systematic  use  of  large  numbers  of  traps, 
preferably  of  the  guillotine  type  shown  in  Fig.  152.  They  have  not 
the  cunning  of  the  rat  so  that  they  are  much  more  easily  trapped,  using 
the  same  baits  mentioned  above  for  rats.  Flour  is  often  a  very 
effective  bait  for  mice. 

Of  more  serious  importance  to  the  farmer  and  fruit  grower  are  the 


246 


ECONOMIC   ZOOLOGY 


so-called  field  or  short-tailed  mice,  or  voles,  of  which  there  are  over 
fifty  kinds  known  in  the  United  States.  For  convenience  they  may  be 
considered  in  two  groups,  the  "meadow  mice,"  genus  Microtus,  and  the 
"pine  mice,"  genus  Pitymys,  Fig.  156.  The  latter  may  be  distinguished 


P 


FIG.  156. — Upper  figure,  meadow  mouse,  Microtus  pennsylvanicus.  X%. 
Lower  figure,  pine  mouse,  Microtus  (Pitymys)  pinetorum.  X%.  (From  Lantz, 
Meadow  Mice  in  Relation  to  Agriculture.) 

from  the  former  by  its  closer,  smoother  fur,  its  reddish-brown  color  and 
its  subterranean  habits. 

The  meadow  mice  make  smooth,  branching  runs  on  the  surface  of 
the  ground,  beneath  the  grass  and  leaves;  the  winter  nest  is  under 
ground,  the  summer  nest  is  a  large  ball  of  dried  grass  on  the  surface 
of  the  ground.  These  mice  are  found,  especially  in  open  fields,  in 


MAMMALIA 


247 


most  parts  of  North  America,  and  at  times  have  been  known,  for  some 
reason,  to  increase  to  such  an  extent  as  to  be  a  most  serious  pest. 
They  produce  several  litters  a  year,  with  from  5  to  10  in  a  litter. 


FIG.   157. — Apple  tree  5  inches  in  diameter  girdled  by  prairie  meadow  mice,  Microtus 
austerus.     (From  Lantz,  Meadow  Mice  in  Relation  to  Agriculture.) 

The  meadow  mice  are  injurious  to  crops  of  all  kinds,  grain,  vege- 
tables and  fruit.  When  in  especially  large  numbers  their  damage  is 
proportionately  greater;  for  example:  in  1906-8  a  pest  of  meadow  mice 
destroyed  the  alfalfa  crop  over  an  area  of  some  18,000  acres  in  Nevada, 


248  ECONOMIC   ZOOLOGY 

causing  an  estimated  loss  of  fully  $250,000;  had  the  trouble  been  handled 
in  its  beginning,  in  the  way  to  be  presently  described,  a  large  part  of 
this  loss  might  have  been  avoided. 

Another  way  in  which  the  meadow  mice  do  serious  damage  is  by 
girdling  young  trees  of  all  sorts,  but  especially  fruit  trees.  They  gnaw 
off  the  bark  at  the  surface  of  the  ground,  the  girdled  area  sometimes 
extending  a  short  distance  below  the  ground,  Fig.  157.  If  the  injury 
be  not  too  great  the  tree  may  be  saved  by  piling  up  the  soil  over  the 
wound  to  prevent  evaporation  until  it  has  time  to  heal;  bridge  grafting 
is  sometimes  used  to  save  large  or  valuable  trees.  While  small  trees 
are  especially  subject  to  attack,  fruit  trees  of  large  size  are  sometimes 
injured  or  killed  and  the  damage  to  a  large  orchard  may  amount  to 
thousands  of  dollars. 

Since  the  remedies  for  the  meadow  mice  are  about  the  same  as  for 
pine  mice,  they  will  be  discussed  after  a  brief  description  of  the  latter 
group. 

Pine  mice  are  common  over  all  of  the  eastern  part  of  the  United 
States,  especially  in  wooded  regions,  or  in  fields,  surrounded  by  timber; 
they  are  not  found  in  open  plains.  As  has  been  said  they  are  burrow- 
ing forms,  making  trails  that  can  only  be  distinguished  from  those  made 
by  moles  by  their  somewhat  smaller  diameter  and  by  the  occasional 
small  opening  to  the  surface.  Because  of  this  burrowing  habit  they 
are  almost  universally  confused  with  and  called  "moles,"  and  where 
they  are  abundant  the  farmer  usually  complains  of  the  damage  done  by 
moles.  It  will  be  remembered  that  the  mole  is  an  insectivorous  creature 
and  is,  as  a  rule,  a  very  useful  animal  to  the  farmer  since  it  eats  grubs 
and  other  subterranean  insects  that  birds  ordinarily  do  not  see.  The 
pine  mouse  may  even  follow  along  in  the  burrows  made  by  the  mole 
and  it  is  he  who  does  the  damage  while  the  innocent  mole  gets  the  blame. 

By  opening  the  tunnel  and  inserting  a  couple  of  fingers  it  is  usually 
possible  to  tell,  by  its  diameter,  whether  a  mole  or  a  pine  mouse  made  the 
burrow. 

In  some  sections  the  pine  mouse  is  a  terrible  pest;  it  will  follow  along 
a  row  of  newly  planted  corn  and  eat  every  grain  for  a  long  distance; 
sometimes  two  or  three  plantings  will  have  to  be  made  before  a  stand 
is  secured.  In  the  same  way  potatoes  and  other  vegetables  are  de- 
stroyed. In  the  eastern  United  States  the  pine  mice  perhaps  do  more 
damage  to  orchard  and  small  trees  than  do  the  meadow  mice.  Since 


MAMMALIA  249 

they  girdle  the  trees  beneath  the  surface  of  the  ground  their  presence 
is  often  not  noticed  until  the  trees  begin  to  wither  and  die.  They  not 
only  girdle  the  trees  but  frequently  cut  the  roots  entirely  through. 
While  not  so  prolific  as  the  meadow  mice  their  protected,  under- 
ground life  makes  up  for  their  slower  breeding. 

In  destroying  field  mice  there  are  three  distinct  lines  of  attack: 
traps,  poisons  and  clean  cultivation. 

In  some  cases,  especially  on  small  areas,  an  ordinary  good  type  of 
mouse  trap  may  be  used  to  advantage.  It  may  be  baited  with  some 
sort  of  grain  or  it  may  be  set  in  the  runways  unbaited,  so  that  the 
mice  may  run  over  and  spring  it  by  accident.  Fifteen  or  twenty 
traps  per  acre  may  be  used  for  several  weeks. 

In  most  cases  it  will  probably  be  better  to  use  poison,  especially 
over  large  areas  and  when  the  mice  are  very  numerous.  Strychnine  is 
generally  used  and  various  substances  are  employed  as  bait.  Lantz 
recommends  the  following  formulae: 

Dry  Grain  Formula. — Mix  thoroughly  i  ounce  of  powdered  strychnine 
(alkaloid),  i  ounce  powdered  bicarbonate  of  soda,  and  Y%  ounce  (or  less) 
of  saccharine.  Put  the  mixture  in  a  tin  pepper  box  and  sift  it  gradually 
over  50  pounds  of  crushed  wheat  or  40  pounds  of  crushed  oats  in  a  metal 
tub,  mixing  the  grain  constantly  so  that  the  poison  will  be  evenly  distributed. 

"  Wet  Grain  Formula. — Dissolve  i  ounce  of  strychnia  sulphate  in  2  quarts 
of  boiling  water.  Dissolve  2  tablespoonfuls  of  laundry  starch  in  ^  pint  of 
cold  water.  Add  the  starch  to  the  strychnine  solution  and  boil  for  a  few 
minutes  until  the  starch  is  clear.  A  little  saccharine  may  be  added  if  desired, 
but  it  is  not  essential.  Pour  the  hot  starch  over  i  bushel  of  oats  in  a  metal 
tub  and  stir  thoroughly.  Let  the  grains  stand  over  night  to  absorb  the 
poison. 

"Potato  Formula. — Cut  sweet  potatoes  into  pieces  about  as  large  as  good- 
sized  grapes.  Place  them  in  a  metal  pan  or  tub  and  wet  them  with  water. 
Drain  off  the  water  and  with  a  tin  pepper  box  slowly  sift  over  them  powdered 
strychnine  (alkaloid  preferred),  stirring  constantly  so  that  the  poison  is 
evenly  distributed.  An  ounce  of  strychnine  should  poison  a  bushel  of  the  cut 
bait." 

Chopped  alfalfa  hay  may  also  be  used  and  has  the  advantage  over 
the  grain  bait  that  it  does  not  endanger  the  life  of  birds.  An  ounce  of 
strychnia  sulphate  dissolved  in  2  gallons  of  hot  water  will  poison  30 
pounds  of  the  alfalfa  if  it  has  been  moistened  with  water  first.  The 


250  ECONOMIC  ZOOLOGY 

potatoes  have  the  same  advantage  over  the  grain,  but  they  will  freeze 
in  cold  weather.  The  dry  formula  will  keep  indefinitely  while  the 
wet  may  ferment. 

In  distributing  the  poisoned  baits  a  teaspoonful  of  the  grain  or  a 
piece  of  potato  is  put  at  each  place.  If  meadow  mice  are  the  pest 
that  it  is  desired  to  kill  the  bait  is  put  on  the  ground  in  their  runways, 
but  to  protect  the  birds,  if  grain  be  used,  it  should  be  covered  with  a 
piece  of  bark,  wood,  stone  or  bush  of  some  sort  so  that  birds  will  not 
see  it;  small  boxes,  pieces  of  tiles,  tin  cans,  etc.,  can  be  used. 

If  pine  mice  are  the  pest,  the  bait  of  whatever  kind,  may  be  dropped 
into  the  open  holes,  or  holes  may  be  made  into  the  tunnels  with  a 


FIG.  158. — Field  mouse  skulls  taken  from  pellets  found  under  owl  roost  in 
Smithsonian  tower,  Washington,  D.  C.  (From  Lantz,  Field  Mice  as  Farm  and 
Orchard  Pests.) 

sharpened  stick  and  the  bait  dropped  in,  so  that  bird  life  is  not 
endangered. 

As  in  the  case  of  rats,  an  ounce  of  prevention  is  here  worth  a  pound 
of  cure,  and  this  may  often  be  secured  by  clean  cultivation  of  fields  and 
orchards,  thus  removing  all  hiding  places  and  destroying  runways 
and  nests.  An  orchard  that  is  overgrown  with  weeds  and  grass  is  far 
more  often  attacked  by  mice  than  one  that  is  clean. 

One,  if  not  the  chief,  reason  for  the  great  numbers  of  field  mice  in 
our  farming  communities  is  the  useless  and  senseless  destruction  of 
their  natural  enemies.  Of  these  enemies  some  are  birds,  some  are 


MAMMALIA  251 

mammals  and  a  few  are  reptiles.  Although  they  have  already  been 
noted  a  few  of  them  will  be  here  recalled.  Probably  the  most  useful 
of  the  natural  enemies  of  field  mice  are  the  owls.  Fig.  158  is  striking 
evidence  of  the  feeding  habits  of  owls.  In  360  pellets  of  the  long-eared 
owl  Dr.  Fisher  found  349  skulls  of  meadow  mice. 

From  its  habit  of  living  near  dwellings  the  familiar  little  screech  owl 
is  also  useful  as  a  destroyer  of  house  mice,  as  well  as  field  mice,  not  to 
mention  English  Sparrows.  With  the  possible  exception  of  the  great 
horned  owl,  the  owls  should  be  rigorously  protected.  Most  of  the 
hawks,  herons,  cranes,  gulls,  shrikes,  crows,  cuckoos,  and  other  of  the 
larger  birds  are  also  useful  as  destroyers  of  field  mice. 

Among  the  mammals  that  prey  on  field  mice  are  the  skunks,  weasels, 
opossums,  raccoons,  foxes,  wildcats,  coyotes,  etc.,  also  domestic  cats 
and  dogs.  Possibly  the  wild  and  domestic  cats,  especially  the  latter, 
do  more  harm  than  good,  but  it  is  likely  that  in  most  localities  the  others 
much  more  than  pay  for  the  few  birds  and  chickens  they  destroy 
by  the  numberless  rodents  they  eat.  This  is  especially  true  of  the 
skunks  which  are  inveterate  hunters  of  field  mice,  grubs  and  other  pests, 
and  very  seldom  molest  poultry  yards.  The  value  of  their  hides  causes 
them  to  be  so  persistently  hunted  that  in  many  sections  they  have 
been  nearly  exterminated.  It  might  be  well  if  the  sale  of  their  skins 
should  be  prohibited.  Black  snakes,  bull  snakes,  house  snakes  and 
other  of  our  larger  snakes  are  excellent  mousers,  or  even  ratters  and 
should  be  protected. 

Most  of  the  natural  enemies  of  mice  mentioned  above  are  also  very 
useful  as  destroyers  of  rats.  Those  that  are  too  small  to  attack  a  full 
grown  rat  could  easily  handle  a  young  one  and  it  is  thought  by  some  that 
a  skunk  or  even  a  weasel  will  not  attack  poultry  so  long  as  there  are 
rats  about  the  premises. 

Farmers  are  slowly  learning  to  realize  that  black  snakes  are  very  use- 
ful animals  to  have  about  their  barns,  some  of  them  claiming  almost 
complete  freedom  from  loss  by  rats  because  of  the  presence  of  several 
large  black  snakes  that  they  carefully  guard  against  injury.  The 
author  has  talked  to  several  farmers  who  made  this  claim.  It  is  often 
difficult  to  prevent  ignorant  hired  men  (especially  negroes)  from 
killing  every  snake,  skunk,  weasel,  hawk,  etc.,  that  they  see. 

Ground  Squirrels. — These  serious  pests  are  found  in  most  of  the  west- 
ern States,  where  they  cause  an  annual  loss  of  many  millions  of  dollars, 


252 


ECONOMIC  ZOOLOGY 


though  their  most  serious  menace  is  due  to  the  fact  that  they  are  carriers 
of  bubonic  plague,  which  they  catch  from  rats.  Several  cases,  some  of 
them  fatal,  have  been  traced  to  ground  squirrels,  and  their  destruction 
is  thus  seen  to  be  especially  important. 

Of  the  numerous  species  one  of  the  best  known  is  the  California, 
Beechey,  or  Digger  ground  squirrel,  Citellus  beecheyi,  which  is  of 
about  the  same  size  and  general  appearance  as  the  eastern  gray  squirrel, 
though  not  so  handsome  an  animal.  It  can  climb  trees  for  its  food,  but, 


FIG.   159. — Mound  of  California  ground  squirrel  in  oats  field. 
straying  Rodent  Pests  on  the  Farm.) 


(From  Lantz,  De- 


as  its  name  indicates,  it  lives  on  and  in  the  ground,  throwing  up  rounded 
mounds  of  dirt  from  its  subterranean  burrows,  Fig.  159.  It  eats 
almost  all  kinds  of  vegetable  matter — fruits,  nuts,  plants,  grain  in 
the  ear  and  newly  planted — but  especially  grain.  It  carries  its  food 
in  its  cheek  pouches  and  stores  it  underground  for  future  "use.  At  times 
it  injures  the  fruit  and  nut  trees  by  gnawing  the  bark.  It  has  been 
known  to  carry  off  large  quantities  of  drying  fruit.  Besides  this,  it 
often  does  serious  damage  to  irrigation  ditches  and  other  waterways. 
There  are  several  methods  that  may  be  used  to  exterminate  this 


MAMMALIA 


253 


pest  but,  owing  to  a  lack  of  cooperation  among  adjacent  landholders, 
they  are  often  not  as  effective  as  they  should  be. 

The  animal  breeds  once  a  year,  with  from  five  to  eleven  in  a  litter, 
and  though  it  is  a  much  less  rapid  breeder  than  the  brown  rat  it  soon 
multiplies  when  not  actively  fought.  A  hundred  or  more  may  some- 
times be  in  sight  at  one  time,  in  an  active  colony. 

Perhaps  the  most  effective  method  of  destruction  is  by  means  of 
poisons,  of  which  strychnine  is  to  be  recommended.  Grain  is  coated 
with  strychnine,  as  described  for  killing  field  mice,  and  this  poisoned 


PIG.   1 60. — Ground  squirrels,  Citellus  beecheyi,  killed  by  poisoned  green  barley  heads 
at  mouth  of  burrow.     (From  Merriam,  The  California  Ground  Squirrel.) 

bait  is  scattered  about  the  holes  and  runs,  preferably  during  the  dry 
season;  the  animals  are  thus  killed  in  large  numbers.  As  a  protection 
for  birds  barley  is  recommended,  the  squirrels  eat  it  readily  and  birds 
very  seldom  do.  It  was  found  that  it  was  better  to  use  grain  that  had 
been  merely  coated  with  the  strychnine  rather  than  soaked  in  it,  be- 
cause the  cheek  pouches,  in  which  the  grain  is  carried,  are  more  quickly 
susceptible,  to  poison  than  is  the  stomach  and  the  food  does  not  have 
to  be  eaten  before  the  animal  is  killed.  The  cost  of  poisoning  in  this 
way  varies,  of  course,  with  the  cost  of  the  materials  and  the  labor  but 
it  is  only  a  few  cents  an  acre,  since  100  pounds  of  the  grain  will  be 
sufficient  for  200  to  300  acres. 


254  ECONOMIC  ZOOLOGY 

Another  more  expensive  method,  that  may  be  used  to  kill  any 
animals,  that  may  escape  the  poison,  is  to  suffocate  them  in  their  bur- 
rows with  a  gas,  preferably  carbon  bisulphid.  A  tablespoonful  of  the 
crude  liquid  is  poured  on  a  corncob,  a  piece  of  dried  horse  manure  or 
some  other  absorbent  substance  and  is  thrust  as  far  as  possible  in  the 
hole,  just  as  is  done  for  killing  rats  in  outdoor  burrows,  and  the  hole  is 
closed  with  dirt.  If  properly  done  it  will  kill  every  squirrel  in  the  bur- 
row, provided  all  the  holes  are  closed;  this  method  is  best  used  during 
wet  weather  when  the  gas  cannot  so  well  escape  through  pores  in  the 
earth.  Figure  160  shows  a  number  of  squirrels  killed  by  poisoned  barley, 
used  while  still  in  the  head.  Buzzards  eat  the  poisoned  squirrels  ap- 
parently without  being  injured  by  the  poison. 

Under  some  circumstances  traps  can  be  used  to  advantage  in  squir- 
rel campaigns,  probably  the  strong  guillotine  traps  mentioned  and 
figured  in  connection  with  rats  being  the  best. 

Where  only  a  few  animals  are  present  they  may  be  shot  with  rifles 
or  shot-guns;  in  this  case  the  animals,  especially  the  young,  may  be 
used  for  food,  though  there  is  danger,  in  some  cases  from  handling 
them,  on  account  of  the  bubonic  plague. 

As  in  the  case  of  field  mice  there  are  numerous  animals  that  serve 
to  check  the  increase  in  numbers  of  the  ground  squirrels  and  the  de- 
struction by  man  of  these  natural  enemies  will  result  in  an  increase  in 
the  numbers  of  the  pest.  Among  these  animals  are  the  golden  eagles, 
coyotes,  foxes,  badgers,  bobcats,  etc. 

Planted  corn  may  be  protected  from  ground  squirrels  and  some 
other  animals  by  coating  it  with  coal  tar. 

Rabbits. — More  than  two  dozen  species  of  rabbits  occur  in  North 
America;  they  fall  rather  naturally,  according  to  size  and  habits,  into 
two  groups:  the  larger  forms  (genus  Lepus),  including  the  jack  rabbits, 
snowshoe  rabbits,  etc.,  are  found  mostly  west  of  the  Mississippi.  The 
smaller  forms  (genus  Sylvttagus),  generally  called  "  cottontails "  occur 
in  all  of  the  States  of  the  Union,  Fig.  161. 

Rabbits  raise  from  two  to  four  litters  a  year  with  an  average  of  four 
per  litter,  the  rate  of  breeding  varying  with  the  species.  They  are,  as 
adults,  strictly  vegetarian,  and  while  they  prefer  certain  foods  they 
will  when  hungry  eat  practically  any  kind  of  vegetable  matter.  Since 
they  often  do  very  serious  damage  to  truck  gardens,  melons,  clover, 
alfalfa,  fruit,  and  nursery  trees,  etc.,  their  repression  is  sometimes  an 


MAMMALIA 


255 


important  matter.  Their  value  as  food  is  considerable,  however,  so 
that  it  is  often  better  and  cheaper  to  protect  the  crops  then  to  try  to 
destroy  the  rabbits. 

In  many  sections  they  are  so  reduced  in  numbers  by  hunters  that 
no  further  efforts  are  necessary  to  handle  the  problem.  In  the  west 
where  the  tall,  long-legged  jack  rabbits  abound  they  are  sometimes 
rounded  up  and  killed  by  the  thousands  in  rabbit  drives,  by  men  on 
horseback  aided  by  dogs.  In  some  States  they  are  protected  by  law 
except  during  a  certain  brief  open  season  and  in  a  few  cases  a  farmer 


PIG.    161.  —  Cottontail    rabbit,     Sylvilagus     sp.,    in     its    "form." 

Lantz,  Cottontail  Rabbits  in  Relation  to  Trees  and  Farm  Crops.) 


(From 


cannot  kill  them  on  his  own  lands  even  though  they  may  be  seriously 
damaging  his  crops.  In  other  States  they  may  be  killed  at  any  time. 

It  is  usually  only  where  they  have,  for  some  reason,  become  exceed- 
ingly numerous  that  they  are  a  serious  pest.  The  best  known  illustra- 
tion of  a  serious  rabbit  pest  is  seen  in  Australia,  where  in  a  few  years 
they  overran  the  country  and  were  a  terrible  plague.  In  a  single  drive 
in  Australia  from  10,000  to  20,000  rabbits  have  been  killed. 

Besides  the  use  of  dog  and  gun  there  are  various  methods  of  reducing 
the  numbers  of  rabbits.  One  of  those  is  by  the  use  of  traps,  which  are  of 


256 


ECONOMIC  ZOOLOGY 


various  kinds.  The  familiar  box  trap  with  a  trigger  and  falling  door  is 
effective.  In  open  country,  where  hiding  places  are  scarce,  the  Walms- 
ley  tile  trap,  Fig.  162,  is  said  to  be  very  effective.  The  figure  scarcely 


FIG.   162. — Vertical  section  of  a  Walmsley  tile  trap  for  rabbits.      (From  Lantz, 
Cottontail  Rabbits  in  Relation  to  Trees  and  Farm  Crops.) 

needs  explanation.  A  couple  of  lengths  of  6-inch  tiles  lead  into  a  larger 
T,  with  a  close  cover;  the  whole  affair  is  covered  with  earth,  leaving  as 
natural  an  opening  as  possible.  The  rabbits  seek  shelter  in  this  arti- 


FIG.   163. — A  tile  trap  in  use,  beneath  a  wire  fence.      (From  Lantz,  Cottontail  Rabbits 
in  Relation  to  Trees  and  Farm  Crops.) 

ficial  hovel  and  are  taken  out  by  removing  the  lid  from  the  T;  a  dog  at 
the  other  opening  will  prevent  the  escape  of  the  rabbit  there,  or  a 
sharpened  board  may  be  pushed  into  the  ground  to  close  that  exit. 


MAMMALIA  257 

Such  a  trap  will  last  indefinitely  and  may  be  located  under  a  fence, 
Fig.  163,  or  in  some  other  spot  that  cannot  be  plowed  up. 

Under  some  circumstances  it  might  be  necessary  to  resort  to 
poisoning,  in  which  case  about  the  same  methods  would  be  used  as 
already  described,  observing  the  same  care  to  avoid  poisoning  birds 
and  domestic  animals.  Apple  twigs  may  be  coated  with  strychnia 
and  used  as  bait  with  little  or  no  danger  to  birds. 

It  is  often  cheaper  to  protect  crops  against  rabbits  than  it  is  to  trap 
or  kill  the  animals.  In  the  case  of  trees  which  are  particularly  apt 
to  be  injured  during  snowy,  winter  weather  when  other  food  is  scarce, 
it  is  necessaryjx)  protect  the  lower  parts  of  the  trunks.  This  is  done 
by  either  painting  the  bark  with  some  substance  poisonous  or  distaste- 
ful to  rabbits  or  by  surrounding  it  with  some  material  to  keep  the  ab- 
bits  from  getting  at  the  bark.  Various  washes  have  been  used  with 
greater  or  less  success;  one  of  those  that  seems  to  be  fairly  effective 
is  the  common  lime-and-sulphur  spraying  mixture.  This  may  be  ap- 
plied to  the  trees  with  a  whitewash  brush  and  is  a  fairly  successful 
protection  against  rabbits  and  meadow  mice;  some  users  claim  that  one 
application  will  last  all  winter.  Perhaps  the  best  material  to  use  to 
keep  the  rabbits  away  from  the  trees  is  one-inch  mesh,  galvanized 
wire  netting  18  inches  wide.  This  is  cut  in  pieces  of  sufficient  length 
to  loosely,  surround  the  trees;  it  may  be  kept  from  touching  the 
trees,  and  thereby  allowing  the  rabbits  access  to  the  bark,  by  short 
sticks.  If  a  finer  mesh  be  used  the  trees  will  be  protected  against  mice 
also.  Corn  stalks,  wood  veneers,  gunny-sacking,  etc.,  may  also  be  used, 
though  they  have  the  objection  that  they  serve  as  insect  harbors,  if 
not  removed  in  the  spring.  In  large  orchards  all  of  these  mechanical 
protectors  are  rather  expensive,  either  to  buy  or  to  attach  or  both. 
Feeding  rabbits  in  winter  to  protect  orchards  has  been  successfully  tried. 
Corn,  cabbage,  turnips,  or  the  prunings  of  the  trees  may  be  scattered 
about  the  orchards  for  the  rabbits,  and  mice,  to  eat  when  other  food 
is  scarce. 

To  protect  small  gardens  and  nurseries  and  even  small  orchards 
a  wire  netting  of  iJ/2  inch  mesh  and  24  to  30  inches  wide  may 
be  used  to  fence  out  rabbits.  Two  feet  is  high  enough  and  the 
other  six  inches  may  be  bent  outward  as  a  ground  wire  to  prevent 
rabbits  from  burrowing  under  the  fence;  of  course  snow-drifts  may 
allow  rabbits  to  get  over  such  a  fence. 

17 


258 


ECONOMIC  ZOOLOGY 


Pocket  gopher.  Geomys  bursarius,  Fig.  164.  This  animal  is  found 
in  all  of  the  states  west  of  the  Mississippi  and  in  several  of  those  east  of 
that  river.  It  is  very  destructive  to  crops  and  trees  and  is  often  a 
serious*pest.  It  also  does  serious  damage  by  the  mounds  of  dirt  and 


PIG.   164. — Mississippi   Valley    pocket   gopher,    Geomys    bursarius. 
Lantz,  Directions  for  Destroying  Pocket  Gophers.) 


-     (From 


stones  which  it  throws  out  of  its  burrow,  and  by  burrowing  in  the  banks 
it  causes  leaks  in  the  irrigation  canals. 

It  may  be  destroyed  by  about  the  same  methods  that  have  been  de- 
scribed for  pfne  mice  and  ground  squirrels,  cooperation  among  adjoining 
farmers  being  necessary  to  any  great  success. 


PIG.  165. — Section  of  a  portion  of  tunnels  of  a  gopher  colony,  a,  mounds  of 
loose  soil;  b,  laterals  leading  to  mounds,  usually  closed  with  earth;  c,  main  runway, 
usually  clean.  (From  Lantz,  Directions  for  Destroying  Pocket  Gophers.) 

Probably  strychnia  poisoning  is  the  best  method  of  extermination; 
the  same  formulae  may  be  used  as  given  above  for  field  mice;  the  bait 
should  be  placed  in  the  main  runways,  Fig.  165,  c.  Carbon  bisulphid 


MAMMALIA  259 

may  be 'used  in  damp  weather  as  in  the  case  of  ground  squirrels.  Traps 
may  sometimes  be  used  to  advantage,  either  the  ordinary  steel  trap, 
buried  in  the  floor  of  the  main  runway,  or  some  form  of  the  special 
gopher  traps  that  are  on  the  market.  In  irrigated  and  other  suitable 
districts  the  burrows  may  be  flooded  with  water  and  the  gophers  thus 
run  out  of  their  holes  can  be  readily  killed  with  dogs,  clubs,  etc. 

Rodents  as  Food. — As  noted  above,  rabbits  are  extensively  used  as 
food  both  in  America  and  elsewhere  and  hence  should  not  be  entirely 
exterminated  since,  in  moderate  numbers,  they  do  little  harm  to  the 


FIG.   166. — Porcupine,  Hystrix  cristata.      xKo-     (From  Jordan  and  Heath,  Animal 

Forms,  after  Brehm.) 

farmer.  The  flesh  of  the  jackrabbit,  except  the  young,  is  not  very 
desirable  but  most  of  the  rabbits  furnish  excellent  food.  In  Australia 
they  were  formerly,  and  probably  are  still,  canned  in  large  numbers 
and  exported. 

Squirrels  are  also  extensively  eaten,  but  owing  to  their  smaller  size 
and  less  abundance,  in  most  places,  they  are  of  less  importance  as  an 
article  of  food  than  rabbits.  As  noted  above,  the  ground  squirrels 
are  used  for  food  and  might  be  an  important  article  of  commerce  but 
for  their  connection  with  the  bubonic  plague. 

Muskrats,  whose  importance  as  fur-bearers  has  been  mentioned  in 
connection  with  the  carnivorous  animals,  to  which  group  they  do  not, 


260 


ECONOMIC  ZOOLOGY 


of  course,  belong,  are  also  used  for  food,  and  efforts  are  being  made  to 
extend  their  use,  under  the  name  of  "marsh  hare"  or  other  trade  names. 
Woodchucks,  beavers,  porcupines,  Fig.  166,  guinea  pigs  and  other 
rodents  may  also  be  eaten  but,  with  the  exception  of  the  last  named, 
are  not  sufficiently  numerous  to  be  of  much  economic  importance,  in 
most  localities.  Even  rats  and  mice  are  eaten  in  many  countries,  but 
are  not  likely  to  become  popular  among  Caucasians,  though  they 
have  been  eaten  during  sieges  when  food  was  very  scarce. 


PIG.   167. — Two-toed  sloth,    Choloepus    didactylus.      X%.     (From    Ingersoll,    The 
Life  of  Mammals,  after  Sanborn,  N,  Y.  Zool.  Soc.) 

Edentata.  Sloth,  Armadillos,  Anteaters. — These  animals  are 
found  almost  entirely  in  South  America,  though  the  Armadillo  is  found 
in  the  extreme  southern  part  of  the  United  States,  and  related  forms 
inhabit  the  eastern  hemisphere.  As  indicated  by  the  name  they  are 
either  without  teeth  in  the  adult  condition  or  have  imperfect  teeth— 
without  roots  or  enamel.  The  incisors  and  canines  are  rarely  present. 

Three  families  of  Edentates  are  recognized:  the  sloths   (Brady- 


MAMMALIA 


261 


podidae),  Fig.  167;  the  American  ant  eaters  (Myrmecophidae),  Fig.  168; 
and  armadillos  (Dasypodidae),  Fig.  169. 


(From 


FIG.   168.  —  The  great  ant-eater  of  Brazil,  Myrmecophaga  jubata. 
Ingersoll,  The  Life  of  Animals,  after  Beddard.) 

Economically  this  is  an  unimportant  order.     The  great  anteater 
or  ant-bear  may  reach  a  length  of  7  feet;  in  spite  of  its  size  its  food 


FIG.    169. — Armadillo,   "Peludo,"   Dasypus  sexcinctus.      xMo-     (From   Ingersoll, 
The  Life  of  Animals,  after  Sanborn,  N.  Y.  Zool.  Soc.} 

consists  of  ants  which  it  captures  by  means  of  a  long  slender  tongue. 
It  is  used  to  some  extent  by  the  natives  as  food. 


262 


ECONOMIC   ZOOLOGY 


The  sloths  are  arboreal  forms  that  move  about  with  the  deliberation 
that  might  be  expected  from  their  names.  They  are  vegetarians  and, 
except  for  some  possible  use  as  food,  have  no  special  economic  value. 
The  armadillo  is  represented  in  Texas  by  one  or  two  species. 
The  nine-banded  armadillo,  Dasypus  (Tatusia)  novemcinctus  texanus, 
Fig.  169,  is  a  curious  armor-covered  little  animal  whose  body  is  about 
1 8  inches  in  length.  It  defends  itself  by  vigorous  use  of  its  large  claws, 
rather  than  by  rolling  up  into  a  ball  as  is  commonly  said.  It  is  largely, 
though  not  entirely,  insectivorous  and  hence  is  useful  to  man.  It  is 

killed  by  the  thousands  annually,  and 
is  made  into  the  well-known  Armadillo 
baskets  by  removing  the  soft  parts 
and  binding  the  tail  around  to  the 
mouth  to  serve  as  a  handle.  Doubt- 
less it  will  sooner  or  later  be  exter- 
minated by  this  ruthless  slaughter. 

The  armadillos  are  also  used  as 
food  and  are  said  to  be  very  palat- 
able. 

Primates.  Monkeys,  Apes, 
Man,  Etc. — This  order,  though  it 
contains  the  so-called  " highest"  of 
the  animals,  is  of  comparatively  little 
economic  importance  unless  we  con- 
sider man's  importance  to  himself. 

Most  of  the  Primates  are  arbo- 
real animals,  living  in  the  warmer 
parts  of  the  world.  Their  limbs  are  usually  prehensile  because  of  the 
fact  that  the  pollex  and  hallux  are  opposable  to  the  other  digits.  There 
are  almost  always  five  digits  ending  in  flat  nails  instead  of  sharp  claws. 
The  clavicles  are  well  developed  and  the  orbit  is  completely  surrounded 
by  a  bony  rim.  There  are  nearly  always  two  thoracic  teats,  and  one 
young  is  usually  produced  at  a  birth.  Some  of  the  Primates,  like 
the  lemurs,  are  small  and  somewhat  dog-like  in  form,  others  like  the 
orang-utan  and  the  gorilla,  Fig.  170,  are  larger  and  more  man-like 
in  appearance.  Many,  like  the  common  monkeys,  Fig.  171,  have  a 
long  prehensile  tail  that  is  largely  used  in  climbing;  others  like  the 
orang-utans,  gorilla,  and  chimpanzee  are  tailless.  Owing  to  the  oppo- 


PIG.  170. — The  gorilla,  Gorilla 
gorilla.  X/^5-  (From  Hegner, 
College  Zoology,  after  Flower  and 
Lydekker.) 


MAMMALIA  263 

sability  of  the  hallux  to  the  other  toes,  which  enables  the  foot  to  grasp 
objects  just  as  the  hand  does,  the  Primates  below  man  (whose  hallux, 
of  course  is  not  opposable)  are '  sometimes  called  quadrumana,  four- 
handed  forms. 

As  has  been  said  this  order  is  of  comparatively  little  economic  im- 
portance. In  many  parts  of  the  tropics  .various  species  of  monkeys 
and  even  young  gorillas  are  eaten  and  are  said  to  be  excellent.  Since 
a  skinned  monkey  is  so  like  a  human  child  it  is  possible  that  stories 
of  cannibalism  may  have  often  arisen  from  the  eating  of  these  lower 
Primates. 


PIG.   171.  —  Monkey  (macaque),  Pithecus  sp. 


In  some  places  monkeys  are  a  considerable  pest,  since  they  travel 
about  in  herds  and  may  be  very  destructive  to  fruits  and  other  property. 

Many  harrowing  stories  have  been  written  about  attacks  of  go- 
rillas upon  man,  but  these  are  probably  exaggerated,  as  some  of  the 
best  authorities  state  that  the  gorilla  will  not  voluntarily  attack  man. 
Doubtless  if  cornered  and  compelled  to  do  so  it  will,  like  almost  all 
animals,  defend  itself;  and  since  a  large  gorilla  weighs  500  pounds 
and  is  strong  in  proportion  it  will  be  easily  imagined  that  an  unarmed 
man  would  be  absolutely  helpless  in  such  a  conflict. 

Ungulata.  Hoofed  Mammals.  —  The  representatives  of  this  order 
are  now  frequently  grouped  into  three  orders:  The  Artiodactyla  or 


264  ECONOMIC  ZOOLOGY 

even- toed  forms;  the  Peris sodactyla  or  odd- toed  forms;  and  the  Pro- 
boscidea,  the  elephants.  Besides  these  another  related  group,  the 
Hyracoidea,  not  true  ungulates,  includes  the  small  oriental  animal, 
the  "coney,"  mentioned  in  the  Bible. 

The  ungulates  are  usually  large  animals  whose  digits  end  in  horny 
hoofs.  They  are  herbivorous  and  are  generally  covered  with  hair  or 
bristles,  rather  than  with  fur.  The  canine  teeth  are  usually  absent 
or  rudimentary  and  the  back  teeth  are  adapted  for  grinding. 

The  artiodactyla  include  most  of  the  game  animals  and  the  domestic 
forms  that  are  used  for  food,  such  as  the  deer,  sheep,  cattle,  goats, 
pigs,  camels,  giraffes,  hippopotami,  etc.  Most  of  these  even-toed 


FIG.  172. — Stomach  of  ruminant  opened  to  show  internal  structures,  a, 
oesophagus;  b,  rumen;  c,  reticulum;  d,  psalterium;  e,  abomasum;  /,  duodenum. 
(From  Hegner,  College  Zoology,  after  Flower  and  Lydekker.) 

forms  are  known  as  ruminants  from  their  habit  of  eating  vegetation 
rapidly  and  later  regurgitating  it  from  a  storage  pouch  or  rumen  and 
then  chewing  it  thoroughly  for  digestion  in  the  other  parts  of  the 
stomach,  Fig.  172.  The  hog  is  the  most  familiar  of  the  non-ruminating 
artiodactyla.  The  perissodactyla  include  the  horse,  ass,  zebra, 
tapir,  rhinoceros,  etc.,  none  of  whom  are  ruminants. 

Most  of  the  ungulate  animals  are  so  familiar  that  no  further  de- 
scription will  be  necessary. 

The  most  important  of  the  ungulats  are,  of  course,  the  ordinary 
domestic  animals,  but  of  these  but  little  need  be  said  here,  since  libraries 
have  been  written  upon  the  different  aspects  of  this  important  subject. 

The  United  States  is  the  greatest  meat-producing  and  meat- 
consuming  country  in  the  world.  In  the  huge  packing  houses  of 


MAMMALIA  265 

Chicago  and  elsewhere  the  handling  of  enormous  quantities  of  beef,  pork 
and  mutton  has  been  developed  into  a  real  science.  Every  part  of  the 
animal  is  used,  in  the  larger  plants,  the  former  waste  products  being 
converted  into  various  by-products,  such  as  fertilizer,  glue,  combs, 
buttons,  gelatine,  plaster,  hair,  tallow,  soap,  perfumery,  glycerine, 
poultry-food,  candles,  oleomargarine,  etc.  The  conversion  of  the 
hides  into  leather  is  an  important  aspect  of  the  cattle  industry. 

Horse. — The  ordinary  uses  of  the  horse  are  too  familiar  to  need  de- 
scription; like  the  dog  the  horse  has  been  a  friend  and  servant  of  man 
from  very  early  times  and  has  been  used  in  many  ways  both  in  peace 
and  in  war.  In  some  countries  it  has  also  been  used  for  many  years,  as 
food,  and  its  use  in  this  way  is  now  very  general,  though  there  is  still 
a  strong  prejudice  against  horse  flesh  in  many  places.  It  is  said  that 
in  1629  a  man  in  France  was  executed  for  eating  horse  flesh  on  a  Satur- 
day in  Lent;  the  meat  is  now  largely  eaten  in  France  and  other  Euro- 
pean countries  and  is  even  exhibited  for  sale  in  some  American  markets. 
There  is,  of  course,  no  reason  why  horse  meat  should  not  be  just  as 
good  as  that  of  any  other  animal. 

Elephant  (Fig.  173). — Two  species  of  elephants  are  usually  de- 
scribed, the  African  and  Indian.  These  huge,  thick-skinned  (pachy- 
derm) animals  are  familiar  to  all.  They  are  almost  hairless,  with  tiny 
eyes  and  huge  waving  ears.  The  muscular  trunk  or  proboscis,  with  the 
nasal  openings  at  the  tip,  is  prehensile  and  is  used  by  its  possessor  for 
securing  food  and  thrusting  it  into  the  mouth,  and  for  many  other 
purposes  for  which  hands  are  commonly  used.  There  are  no  canine 
teeth,  but  a  pair  of  upper  incisors  become  greatly  elongated  to  form 
the  curved  tusks.  They  are  8  to  10  feet  or  more  in  height  and 
may  weigh  five  tons  or  more. 

The  Indian  elephant  is  more  commonly  domesticated,  and  may 
be  easily  tamed  and  trained,  in  a  few  months.  It  has  been  used  in  the 
Orient  for  thousands  of  years,  in  battle,  in  parades,  for  carrying  goods, 
piling  lumber,  etc.  It  seems  to  be  an  unusually  intelligent  animal; 
for  example,  it  exhibits  remarkable  judgment,  while  lifting  a  huge  log 
on  its  tusks,  in  calculating  the  centre  of  gravity  of  the  log  so  that  the 
two  ends,  often  of  unequal  diameters,  will  balance  each  other. 

Wild  elephants  are  captured  in  pits  and  corrals,  trained  decoys 
being  often  employed. 

Besides  as  a  beast  of  burden,  the  elephant  has  great  economic 


266 


ECONOMIC   ZOOLOGY 


importance  as  a  source  of  ivory,  and  the  huge  tusks  that  may  be  useful 
to  him  in  his  natural  environment  are  the  cause  of  his  destruction,  in 
enormous  numbers,  by  man,  9000  to  12,000  being  killed  annually  for 
the  ivory  trade.  A  medium-sized  tusk  weighs  60  pounds;  the  largest 
size  200  pounds. 

The  flesh  of  the  elephant  is  used  as  food  in  some  regions,  the  trunk 
and  feet  being  considered  the  best.  The  feet  are  said  to  be  cooked  by 
burying  them  in  the  earth  and  building  a  large  fire  on  top  of  the  ground. 


FIG.   173.  —  African  elephant,  Loxodonta  africanus. 

Zoology,  after  Beddard,  from  Baker.) 


(From  Hegner,  College 


Camel.  —  Two  main  species  of  the  genus  Camelus  are  found  in  the 
Orient;  the  two-humped  Bactrian  camel  of  the  Asiatic  plateaus, 
and  the  one-humped  Arabian  camel  or  dromedary.  The  former  is 
thickly  haired  and  is  adapted  to  the  cold  of  high  altitudes;  both 
are  adapted  to  life  in  desert  places  by  the  possession  of  wide 
soft  feet;  tightly  closing  nostrils  (as  a  protection  during  sand  storms); 
a  mass  of  stored  food  in  the  hump  or  humps;  and  particularly,  by  the 
possession  of  tightly  closing  water  cells  in  the  walls  of  the  rumen  and 
reticulum  of  the  stomach,  in  which  15  or  20  quarts  of  water  may  be 
stored,  upon  which,  it  is  said,  the  animal  may  live  for  nearly  a  week. 
It  is  even  reported  that  hard-pressed  travelers  have  been  saved  from 


MAMMALIA  267 

death  by  killing  their  camels  and  drinking  the  water  still  stored  in  the 
water-cells  of  the  stomach.  Each  water  cell  is  a  small  pocket  with 
the  opening  closed  by  a  sphincter  muscle  to  hold  in  the  water.  "  One 
celebrated  traveler  mentions  the  case  of  a  camel  that  Had  been  dead 
for  ten  days,  and  yet  had  no  less  than  three  pints  of  not  unpleasant 
water  still  remaining  in  its  stomach." 

After  the  flesh  of  the  hump  has  been  reduced  by  a  prolonged  fast 
it  may  take  three  or  four  months  to  be  replaced. 

Camels  have  been  domesticated  for  long  ages  and  are  known, 
at  present,  only  in  the  domestic  state.  Various  races  are  bred  and, 
like  horses,  are  adapted  for  different  uses,  chiefly  as  bearers  of  heavy 
loads  and  for  rapid  travel  as  saddle  animals ;  a  pack  animal  may  carry 
600  pounds  or  more  at  a  speed  of  two  to  three  miles  an  hour;  a  saddle 
animal  is  said  to  be  able  to  cover  a  distance  of  100  miles  in  a  day.  The 
use  of  the  "ship  of  the  desert"  in  caravans  is  too  well  known  to  need 
further  discussion.  They  are  also  of  value  to  their  possessors  for  their 
hair,  which  is  woven  into  cloth,  for  their  milk  that  is  largely  used  as  a 
food  and  to  some  extent  for  their  flesh,  which  is  occasionally  eaten. 
The  value  of  camels  is  about  that  of  horses.  At  the  time  of  the  gold 
rush  to  California,  in  1850,  some  camels  were  tried,  unsuccessfully,  on 
our  western  deserts;  they  were  later  allowed  to  run  wild. 

Belonging  to  the  same  family  (Camelidae)  with  the  camels  are  the 
Llama  and  Alpaca,  which  have  been  domesticated  for  centuries  by  the 
Peruvians.  They  are  both  smaller  than  the  camel.  The  former  is 
used  as  a  beast  of  burden,  the  latter  is  now  extensively  bred  in  South 
Africa  for  its  wool,  which  is  so  long,  sometimes,  that  it  reaches  the 
ground. 

American  Bison,  Bison  bison  (Fig.  174). — This  magnificent  animal 
(commonly  called  the  buffalo),  as  mentioned  above,  once  roamed  the 
plains  of  the  western  United  States  in  countless  numbers.  It  had  been 
used  by  the  Indians  from  time  immemorial,  apparently  without  ap- 
preciable diminution  in  numbers,  but  with  the  advent  of  the  so-called 
"civilized"  white  man,  armed  with  firearms,  its  numbers  rapidly  di- 
minished until  now,  except  for  a  few  hundreds  of  captive  individuals, 
cared  for  in  private  ranges  and  elsewhere,  this  king  of  American  animals, 
shown  on  our  new  five-cent  pieces,  is  practically  extinct.  "Buffalo" 
robes  that  were  cheap,  a  generation  or  two  ago  are  now  no  longer  on 
the  market.  It  was  said  that  many  of  the  settlers  killed  the  bison  and 


268 


ECONOMIC   ZOOLOGY 


used  nothing  but  the  tongue,  and  many  were  killed  purely  for  sport, 
the  carcass  being  left  untouched  on  the  plains.  This  wanton  slaughter 
was  a  disgrace  to  the  American  people,  and  probably  but  for  the  public 
spirit  of  the  members  of  the  American  Bison  Society  and  other  indi- 
viduals the  race  would  now  be  as  extinct  as  the  passenger  pigeon. 

Hippopotamus  and  Rhinoceros. — These  huge  pachydermatous  forms 
are  used  to  a  considerable  extent  by  the  natives  of  Africa  as  food,  the 
flesh  being  like  coarse  beef. 


FIG.   174.  —  The     American    bison,    Bison   bison.      X 

Zoology,  after  Beddard.') 


-     (From    Hegner,    College 


Deer.  —  The  various  species  of  the  deer  family  (Cermda)  are  among 
the  most  useful  of  our  native  animals,  and  were  formerly  of  great  eco- 
nomic importance,  before  their  numbers  were  reduced  by  indiscriminate 
slaughter.  Venison  in  medieval  Europe  and  in  the  early  days  in 
America  was  the  common  meat  of  the  table,  while  now  it  is  seldom 
seen  except  at  frontier  points  in  the  United  States  and  Canada.  It  is 
one  of  the  most  easily  digested  of  foods  and  hence  would  be  invaluable 
for  invalids.  According  to  tables  published  by  the  Scientific  American 
venison  requires  one  hour  for  digestion,  as  compared  to  one  and  one- 
half  hours  for  raw  eggs,  three  hours  for  mutton  and  five  hours  for 
pork  or  veal. 

Besides  their  value  as  a  source  of  meat,  deer  are  also  important  be- 


MAMMALIA  269 

cause  of  their  hides  and  their  horns,  not  to  mention  their  usefulness  as 
beasts  of  burden,  to  be  discussed  later. 

The  value  of  the  hides  for  leather  varies  with  the  size  and  the  species 
of  deer.  In  olden  times  elk-hide  trousers  were  frequently  worn  and 
were  said  to  last  several  generations.  The  American  Indians,  in  some 
sections,  still  make  moccasins,  coats  and  other  articles  from  deer 
skin.  Many  thousands  of  deer-hides  were  formerly  sold  each  year  in 
England,  but  the  trade  has  now  largely  disappeared. 

In  most  species  of  deer  (except  a  few  forms  like  the  caribou  or  rein- 
deer), only  the  males  have  horns;  these  are  solid  outgrowths  of  the 
frontal  bone  that  are  shed  each  year  after  the  mating  season  and  are 
grown  again  as  the  next  mating  season  approaches.  These  hard, 
solid  horns  are  used  in  various  ways:  for  making  "elk-horn"  handles 
for  knives  and  other  implements,  and  for  making  gelatin  and  size 
(used  in  the  manufacture  of  cloth).  Formerly  it  was  a  prominent 
source  of  ammonia,  which  for  that  reason,  is  still  sometimes  sold  under 
the  name  of  "hartshorn."  India  and  Ceylon  were  formerly,  and 
perhaps  still  are,  the  chief  sources  of  supply  for  deerhorn  and  hundreds 
of  thousands  were  killed  annually. 

With  the  advance  of  civilization  the  ranges  of  the  various  deer 
become  more  and  more  restricted,  in  this  country,  until  now  it  will  be 
necessary  to  domesticate  them  if  they  are  to  be  saved  in  sufficient  num- 
bers to  be  of  commercial  value. 

According  to  -Lantz  deer  raising  could  be  highly  profitable  if  the 
game  laws  could  be  changed  (as  they  have  recently  been  in  a  few  states) 
to  allow  the  sale  of  venison  from  private  estates,  just  as  the  meat  of 
other  domesticated  animals  is  handled.  It  is,  of  course  important 
that  deer  and  other  animals  be  protected  in  the  wild  state;  but  that  a 
man  who  buys  a  pair  of  deer  and  raises  a  herd  in  an  inclosure  should 
not  be  able  to  sell  their  meat,  where  and  when  he  pleases,  is  absurd. 
One  great  advantage  in  raising  deer  over  the  raising  of  cattle  is  that 
they  may  be  kept  on  almost  any  kind  of  rough,  mountain  land  that  is 
useless  for  any  other  purpose.  There  are  hundreds  of  square  miles 
of  waste  mountain  lands  in  the  United  States  that  could  be  fenced  and 
used  for  deer  ranges,  just  as  the  level  lands  and  grassy  mountains  are 
used  for  cattle. 

The  largest  of  the  deer  family^is  the  moose,  Alces  americanus,  Fig. 
175,  a  magnificent  animal  as  large  as  a  horse,  whose  head  is  frequently 


270 


ECONOMIC   ZOOLOGY 


seen  in  the  homes  of  the  wealthy  and  is  recognized  by  the  widely 
spreading,  flat  antlers  and  the  curiously  shaped  muzzle.  The  moose 
can  be  raised  under  domestication  and  becomes  tame  and  affectionate. 
It's  chief  use  is  as  a  beast  of  burden  and  it  is  easily  handled  and  driven. 


FIG.  175. — The  Alaska  moose,  Alces  americanus  gigas.  This  is  the  largest  of 
the  deer  family  and  reaches  the  size  of  a  large  horse.  (From  Osgood,  The  Came 
Resources  of  Alaska.) 

It  is  swifter  than  the  reindeer  and  has  such  endurance  that  it  has  been 
known  to  draw  a  sleigh  234  miles  in  a  single  day. 

The  elk  or  Wapiti,  Cervus  canadensis,  Fig.  176,  is  the  largest  of 
the  round-horn  deer  and  is  next  to  the  moose  in  size.  It  formerly 
ranged  over  almost  the  entire  United  States  and  part  of  Canada.  Its 


MAMMALIA  271 

venison  is  perhaps  the  best  of  all  the  family  especially  at  the  time  the 
" velvet"  (the  soft  covering  of  the  newly  formed  horns)  is  shed;  it  is 
better  if  allowed  to  hang  a  few  days  before  it  is  eaten. 

The  elk  is  particularly  well  adapted  to  domestication  because 
of  its  fine  size,  polygamous  habits  and  ability  to  live  on  otherwise  worth- 
less land.  It  breeds  as  fast  and  requires  less  care  than  domestic  cattle. 


PIG.  176. — Rocky  Mountain  wapiti  or  elk,  Cervus  canadensis ;  buck  in  fore- 
ground, doe  in  background;  after  the  moose  the  largest  of  our  deer.  (From  Lantz, 
Raising  Deer  and  Other  Large  Game  Animals  in  the  United  States.) 

It  is  already  successfully  raised  at  several  places  and  could  be  raised 
equally  well  in  many  other  localities.  If  the  laws  of  the  state  will  not 
allow  them  to  be  sold  to  advantage  they  could,  in  many  places,  be 
raised  in  small  numbers  for  home  consumption. 

It  is  mainly  in  times  of  heavy  snow  that  the  elk  have  to  be  given 
other  food  than  that  which  they  get  for  themselves.  Alfalfa  is  perhaps 


272  ECONOMIC  ZOOLOGY 

best,  with  a  little  oats  and  corn;  they  must,  of  course,  have  plenty  of 
water;  also  salt. 

The  enclosure  can  be  fenced  with  five-foot  woven  wire,  which  is 
usually  high  enough;  but  uncastrated  males  four  or  five  years  old  must 
be  strongly  fenced.  A  given  enclosure  will  support  about  as  many 
elk  as  it  would  support  cattle.  Young  stock  can  be  bought  for  breed- 
ing purposes  for  $100  or  less  each.  The  bucks  are  docile  at  most 
times,  but  during  the  breeding  season  they  often  get  very  savage  and 
dangerous,  and  fatalities  have  been  caused  by  them.  The  males  not 
needed  for  breeding  may  be  castrated,  which  not  only  makes  them  gentle 
but  improves  the  meat,  just  as  it  does  with  cattle  and  other  domestic 
animals. 

Adult  males  average  700  to  1000  pounds  in  weight;  females  some- 
what less. 

A  smaller  form  that  may  be  successfully  raised  under  domestica- 
tion is  the  Virginia  deer  or  white  tailed  deer,  Odocoileus  (Caraicus) 
mrginianus,  the  commonest  of  our  deer.  Like  other  deer  it  is  polyga- 
mous, one  male  to  ten  or  twelve  females  being  sufficient  for  breeding 
purposes;  this  makes  it  possible  to  castrate  most  of  the  males  for  the 
same  reasons  that  were  given  for  castrating  the  elk  bucks;  though  not  so 
large,  the  bucks  of  this  species  are  often  very  dangerous  during  the 
rutting  season,  which  is  November.  The  does  breed  at  17  months 
and  have  a  gestation  period  of  seven  months.  The  first  birth 
is  single;  after  that  twins  are  usually  born.  They  eat  grass,  weeds, 
leaves,  acorns,  chestnuts,  in  fact,  almost  anything;  like  the  elk  they 
must  have  salt,  and,  of  course,  water. 

It  is  probable  that  besides  the  above  species  almost  any  of  the  deer 
family  could  be  successfully  and  perhaps  profitably  raised  under 
domestication. 

Reindeer  or  caribou  are  represented  in  northern  North  America, 
according  to  Lantz  by  two  groups,  the  large,  wild,  woodland  caribou, 
Rangifer  caribou,  and  the  less  important,  barren-ground  caribou,  R. 
arcticus  Fig.  171.  These  species,  so  similar  to  the  European  reindeer, 
R.  tarandus,  have  never  been  domesticated,  though  there  seems  to  be 
no  reason  why  they  should  not  be;  and  the  enormous  herds  still  at 
large  in  Newfoundland  would  supply  unlimited  stock. 

In  1892  the  first  domesticated  Lapland  reindeer  were  introduced 
from  Siberia  into  Alaska  by  Dr.  Jackson  of  the  Bureau  of  Education. 


MAMMALIA 


273 


The  deer  were  loaned  to  mission  stations  where  Eskimos  were  trained 
to  care  for  them,  the  superintendents  of  the  stations  reporting  to  the 
Bureau.  Since  1894  the  government  has  appropriated  money  to  con- 
tinue this  work,  and  in  1910  Lantz  estimated  there  were  not  less  than 
23,000  reindeer  in  the  herds.  At  the  end  of  five  years  a  number  of  young 
deer  equal  to  the  number  loaned  each  mission  is  to  be  returned  to  the 


PIG.   177. — Barren  Grounds  caribou,  Rangifer  arcticus. 

The  Life  of  Aniyials.) 


-     (From  Ingersoll, 


government.  At  the  end  of  each  year  of  faithful  service  each  appren- 
tice is  given  two  deer  so  that  in  five  years  he  can  start  in  business 
for  himself,  but  he  is  then  allowed  to  kill  for  meat  and  skin  only  the 
surplus  of  males,  and  he  is  encouraged  to  raise  deer  for  carrying  United 
States  mail,  passengers  and  freight.  He  is  not  allowed  to  sell  female 
deer  except  to  the  Bureau  of  Education  in  order  that  the  business  may 
not  get  out  of  the  hands  of  the  Eskimos. 

18 


274  ECONOMIC  ZOOLOGY 

Through  the  efforts  of  Dr.  Grenfell,  Lapland  reindeer  have  been 
introduced  in  Labrador  and  Newfoundland  with  great  success,  and  it 
is  to  be  hoped  that  this  will  lead  to  the  domestication  of  a  part  of  the 
vast  herds  of  American  reindeer  there  running  wild  in  a  more  or  less  use- 
less state. 

Sirenia.  Sea  Cows  (Fig.  178).— This  order  contains  a  small  number 
of  rather  large  aquatic  mammals  belonging  to  the  genera  Manatus  and 
Dugong;  the  members  of  the  former  genus  live  along  the  Atlantic  coasts 
of  tropical  and  sub-tropical  America  and  Africa;  the  latter  genus  is 
found  along  certain  oriental  seacoasts. 

The  sea-cows  are  probably  so  named  because  of  the  cow-like  shape 
of  their  muzzle  and  because  of  their  habit  of  browsing  upon  s'ub-aquatic 
vegetation  after  the  manner  of  cattle  feeding  upon  grass.  The  Sirenia 
are  devoid  of  posterior  appendages  and  the  anterior  limbs  are  modified 
into  flippers  for  swimming.  At  the  posterior  end  of  the  body  is  a 
bluntly  pointed  tail.  The  bones,  unlike  those  of  the  somewhat  similar 
whales,  are  heavy,  to  enable  the  animal  to  sink  to  the  bottom  where  it 
feeds  upon  sea  weeds  and  other  aquatic  plants.  According  to  some 
observers  it  never  entirely  leaves  the  water,  at  least  in  its  natural 
habitat. 

The  Florida  manatee  was  nearly  exterminated  until  a  fine  of  $500 
was  levied  for  killing  it;  it  is  now  thought  to  be  increasing  in  numbers. 
It  may  be  caught  alive  to  fill  highly  paid  orders  for  exhibition  purposes. 
The  flesh  of  the  Sirenia  forms  a  very  desirable  food  and  in  the  orient 
the  dugong  is  considered  a  royal  dish.  It  is  somewhat  like  pork  and 
the  fat  is  boiled  out  and  used  as  we  use  butter.  It  may  be  dried  or 
salted  and  keeps  well.  The  South  American  monks  consider  the  manatee 
and  other  aquatic  mammals  as  fish,  which  permits  their  being  eaten 
during  fast  days  when  flesh  would  be  prohibited.  The  skin  is  used 
in  making  leather.  The  manatee  is  occasionally  caught  in  the  West 
Indies  and  sold  for  food. 

Except  for  their  comparative  rarity  the  Sirenia  would  be  a  group 
of  considerable  economic  importance. 

Cetacea.  Whales,  Dolphins,  Etc. — The  classification  of  this  order 
is  variously  given  by  different  authors;  by  some  these  forms  are  all  in- 
cluded in  one  order — Cetacea,  with  various  families;  by  later  writers  two 
orders  are  used — Odontoceti,  the  toothed  whales,  and  Mystacoceti,  the 
whalebone  whales. 


MAMMALIA 


275 


FIG.  178.  —  Manatee    or    sea-cow,    Manatus,    sp. 

Life  of  Animals.} 


(From    Ingersoll,    The 


276 


ECONOMIC  ZOOLOGY 


As  a  matter  of  convenience  the  single  order,  Cetacea,  will  be  used 
here,  and  one  or  two  members  of  each  of  the  above  two  groups  will 
be  discussed  from  the  economic  standpoint. 

The  whales  are  wholly  aquatic  in  habits  and  hence  are  fish-like  in 
form.  The  anterior  appendages  are  developed  into  flippers,  the  pos- 


PiG.    179. — Skull   of    Greenland   whale,    Balaena   mysticetus,    showing   whalebone. 
X;H$o-     (From  Hegner,  College  Zoology,  after  Sedgwick,  from  regne  animal.) 

terior  appendages  are  usually  entirely  wanting  and  the  pelvic  girdle 
is  vestigial.  The  tail  is  flattened  vertically  and  is  divided  into  right 
and  left  flukes,  and  by  its  vigorous  up-and-down  motion  propels  the 
animal  with  the  speed  of  a  steamship.  The  body  is  practically  devoid 
of  hair  and  is  surrounded,  beneath  the  skin,  by  a  layer  of  fat  (blubber) 


PIG.   1 80. — The     dolphin,     Delphinus     del-phis.      xKo-     (From     Hegner,     College 
Zoology,  after  Sedgwick,  from  regne  animal.) 

that  serves  to  keep  the  animal  warm  in  the  cold  water  in  which  it 
usually  lives.  The  nostrils  are  in  the  form  of  spiracles  on  top  of 
the  head,  from  which  a  jet  of  moist  breath  causes  the  appearance  of 
"spouting."  The  eyes  are  very  small  and  no  external  ears  are  present. 
In  the  toothed  whales  numerous  teeth  are  present  in  the  adults,  in  the 
whalebone  whales  teeth  are  present  only  in  the  embryos,  the  adults 


MAMMALIA 


277 


being  provided  with  numerous  frayed-out  plates  of  baleen  or  whalebone, 
suspended  from  the  upper  jaw,  Fig.  179  and  serving  to  strain  out  small 
organisms  from  the  water  that  the  whale  gulps  into  its  enormous  mouth 
and  then  forces  out  through  this  whalebone  strainer. 

Among  the  smaller  members  of  the  toothed  forms  are  the  dolphins 
Fig.  1 80,  and  porpoises,  of  which  there  are  several  species,  extending 


PIG.   181. — Sperm  whale,  Physeter  macrocephalus.     (From  Hegner,  College  Zoology.) 

from  5  to  15  feet  in  length.  They  are  familiar  to  most  people  who  have 
taken  ocean  trips,  from  their  habit  of  "playing"  about  the  bows  of 
a  vessel. 

The  sperm  whale,    Physeter  macrocephalus,  Fig.  181,  is  the  largest 
of  the  toothed  whales,  reaching  a  length  of  75  feet. 


••>-.. 


(After   Rabot,    Whale 


PIG.   182. — Sulphur-bottom   whale,   Balaenoptera   musculus. 
Fisheries  of  the  World.) 


The  largest  of  the  whales  is  the  sulphur-bottom,  Balaeoptera 
culus,  Fig.  182,  which,  according  to  Hegner,  reaches  a  length  of  95 
feet  and  weight  of  about  294,000  pounds;  the  late  F.  W.  True,  an  au- 
thority on  the  Cetacea,  gave  the  maximum  length  as  somewhat  less 
than  this.  At  any  rate  this  is  the  largest  living  animal,  and  perhaps 
the  largest  that  has  ever  lived,  for  while  some  of  the  extinct  reptiles  were 
longer,  they  were  probably  not  so  bulky  as  this  whale.  Another  large 


278  ECONOMIC   ZOOLOGY 

whale  is  the  Greenland,  an  Arctic  form  yielding  valuable  oil  and  whale 
bone. 

The  finbacks,  Fig.  183,  and  humpbacks,  Fig.  184,  are  the  forms 
most  commonly  killed  at  present. 


PIG.   183. — Common  finback  whale,  Balaenoptera  physalus.     (After  Rabot,    Whale 
Fisheries   of  the  World.) 

The  killer  whale,  Orca  orca,  is  a  voracious  form,  20  feet  or  more  in 
length,  that  is  very  destructive  attacking  all  marine  animals,  even  the 
largest  whales. 

The  narwhale,  Monodon  monoceras,  is  an  Arctic  form,  one  of  whose 
upper  teeth  is  prolonged  into  a  twisted  horizontal  tusk  5  or  6  feet  in 
length. 


FIG.   184. — North  American  humpback  whale,   Megaptera  nodosa.     (After  Rabot, 
Whale  Fisheries  of  the  World.) 

There  are  numerous  other  species  that  more  or  less  closely  resemble 
those  mentioned  above. 

One  of  the  first  and  most  important  of  the  uses  to  which  whales  have 
been  put  is  the  production  of  sperm  oil.  Oil  has  been  used  for  illumi- 
nation and  other  purposes  for  ages,  probably  since  the  seventh  century. 


MAMMALIA 


279 


It  was  first  obtained  from  whales  that  were  stranded  upon  the  shore, 
then  from  whales  that  were  hunted  at  sea.  The  Norwegian  whale- 
hunters  are  said  to  have  landed  on  Newfoundland  before  the  discovery 


FIG.  185. — Photograph  of  finback  whale,  Balaenoptera  physalus,  taken  at 
Provincetown,  Mass.  (From  True,  The  Whalebone  Whales  of  the  Western  North 
Atlantic.) 

of  America  by  Columbus,  though  this  statement  may  not  be  true.     The 
height  of  the  sperm  oil  business  was  reached  about  1846,  when  in  the 


PIG.   1 86.— A  whale  steamer.     (After  Rabot,  The  Whale  Fisheries  of  the  World.) 

United  States,  more  than  700  vessels  and  40,000  people  were  engaged 
in  the  collection  of  12,000,000  gallons  of  oil  per  year,  valued  at 
$8,000,000;  whalebone  was  also  collected. 


280 


ECONOMIC   ZOOLOGY 


The  discovery  of  petroleum  and  the  diminution  in  the  number  of 
whales  almost  killed  the  business,  so'  that  in  1902  the  whaling  fleet 

of  the  United  States  con- 
sisted of  eight  steamers, 
Fig.  1 86,  and  30  sailing 
vessels;  and  the  total  out- 
put of  the  world  was  about 
3,000,000  gallons  per  year. 
After  a  decade  of  inac- 
tivity the  whale  fishery 
experienced  a  considerable 
revival,  headed  by  the 
Norwegian  hunters  so  that 
an  annual  catch  of  20,066 
whales  was  e s  t i ma  ted 
about  1912.  Numerous 
companies  were  formed  in 
different  countries  with 
stations  in  nearly  every 
part  of  the  colder  regions 
of  the  world.  Along  the 
northern  coast  of  Norway 
the  killing  of  whales  was 
prohibited  for  a  term  of 
years  because  of  the  claim 
of  the  cod  fishermen  that 
it  injured  their  business. 
The  most  prolific  stations 
have  been  those  of  the 
Antarctic  Seas,  where 
whales  were  found  in  great 
numbers;  in  1911,  10,000 
finbacks  and  humpbacks 
were  killed  in  the  Antarctic 
in  the  region  of  South 
America;  in  the  same  year 
the  total  production  of  oil  was  estimated  at  102,000  metric  tons,  and 
large  quantities  of  whalebone,  guano  and  other  valuable  products  were 
also  obtained. 


MAMMALIA 


28l 


This  business  does  not  require  large  capital  and  when  fortune  smiles 
and  good  fishing  grounds  are  found  the  profits  are  enormous.  "In 
two  years  a  company  with  a  capital  of  910,000  francs,  installed  at  South 
Georgia,  twice  distributed  a  dividend  of  130  per  cent,  besides  adding  a 
portion  of  the  profit  to  various  reserve  funds  and  increasing  the  com- 
pany's resources  60  per  cent."  (183). 

The  oil  is  obtained  by  boiling  down  the  blubber,  30  tons  or  more 
of  which  may  be  taken  from  one  whale;  from  10  to  100  barrels  of  oil 
may  be  obtained  from  a  single  whale,  depending  on  the  species  and 
size.  At  the  present  time  the  flesh  and  other  portions  remaining  after 
extraction  of  the  oil  are  made  into  fertilizer,  guano. 


FIG.   1866. — Return  to  port  after  the  chase,  towing  a  whale  on  each  side.     (After 
Rabot,  Whale  Fisheries  of  the  World.) 

'    '        •       '*"~    -'t 

Spermaceti  is  a  wax-like  solid  that  is  obtained  from  a  peculiar  kind 
of  clear  whale  oil  found  particularly  in  the  sperm  whale.  This  oil 
is  found  in  various  parts  of  the  body  but  especially  in  a  large  cavity 
on  the  dorsal  side  of  the  head,  between  the  skull  and  the  integument. 
The  oil  is  given  a  certain  rather  complicated  treatment  and  from 
it  is  extracted  the  spermaceti,  formerly  used  largely  in  the  manufacture 
of  candles. 

Baleen  or  whalebone,  as  noted  above,  occurs  as  long,  fringed  masses 
in  the  mouth  of  various  species  of  whalebone  whales.  It  is  rather  loosely 
attached  to  the  sides  of  the  upper  jaws,  Fig.  179,  187,  and  188,  from 
which  it  is  easily  dug  out  with  axes  and  spades.  The  bowhead  and  right 
whales  supply  the  best  whalebone,  and  as  a  large  bowhead  may  fur- 


282  ECONOMIC  ZOOLOGY 

nish  as  much  as  2000  pounds  of  baleen  together  with  a  hundred  barrels 
of  oil,  to  say  nothing  of  the  guano  and  other  products,  the  value  of  such 
a  catch  is  considerable.  The  record  amount  of  baleen  in  one  animal, 
according  to  Stevenson  (185),  is  3100  pounds. 

The  slabs  of  baleen  may  be  10  to  12  feet  long,  about  a  foot  of 
the  base  being  imbedded  in  the  jaws. 


PIG.  187. — Photograph  of  the  head  of  a  sulphur-bottom  whale,  Balaenoptera 
musculus.  Baleen  station,  Newfoundland.  (From  True,  The  Whalebone  Whales  of 
the  Western  North  Atlantic.) 

The  lower  edges  of  the  slabs  are  frayed  out  into  a  kind  of  coarse, 
hair-like  structure  that  is  clipped  off  and  used  in  making  brushes,  etc. 

When  the.  whale  is  killed  the  jaws  with  the  attached  baleen  are 
hauled  upon  the  deck  of  the  ship,  Fig.  188,  where  the  whalebone  is  re- 
moved, cut  into  slabs  and  thoroughly  washed  and  cleaned  of  any  flesh  or 
foreign  substances.  On  the  voyage  back  to  port  these  slabs  are  further 
split  up,  cleaned  and  tied  into  bundles  of  a  size  convenient  for  handling, 


MAMMALIA 


283 


284 


ECONOMIC  ZOOLOGY 


FIG.   189. — Bundles  of  whalebone  as  received  at  the  factory.     (From  Stevenson, 
Whalebone,  its  Production  and  Utilization.) 


MAMMALIA  285 

Fig.  189.  These  bundles  are  landed  at  the  most  convenient  port; 
San  Francisco  is  the  chief  port  for  the  Arctic  fisheries.  At  the  factories, 
those  of  America  being  principally  in  New  York  City  and  Boston, 
the  baleen  is  split  into  long  slender  strips,  suitable  for  whips,  dress 
stays,  etc.  In  the  early  days  of  whale  fisheries  the  valuable  properties 
of  baleen  were  not  appreciated  and  but  little  of  it  was  brought  to  port. 
It  is  supposed  that  the  first  importation  into  England  was  in  1 594.  The 
price  has  fluctuated  like  that  of  most  commodities,  varying  from  10 
cents  a  pound,  in  early  times,  to  $5  or  $6  a  pound  in  recent  years. 

Many  substitutes  for  whalebone  are  on  the  market,  but  none  of 
them  combines  the  various  useful  characteristics  of  the  real  article. 

Ambergris,  a  curious  light  solid,  sometimes  found  floating  on  the 
sea,  or  lying  on  the  shore,  was  long  a  mystery.  It  is  also  found  in  the 
intestine  of  the  sperm  whale;  it  is  probably  a  morbid  secretion,  com- 
parable, perhaps,  to  the  gall  stones  of  other  mammals.  It  is  mainly 
used  in  making  perfumery,  but  was  formerly  used  as  a  nerve  stimulant, 
in  medicine  and  for  other  medicinal  purposes.  Lumps  worth  as  much 
as  $10,000  have  been  found  in  a  single  whale.  It  is  worth  from  $5  to 
$10  per  ounce. 

Other  ways  in  which  the  cetacea  have  greater  or  less  economic 
importance  might  be  discussed.  For  example  they  are  largely  used  as 
food,  especially  by  the  Japanese;  their  offal,  as  has  been  said,  is  made 
into  fertilizer;  the  tusk  of  the  narwhale  consists  of  valuable  ivory; 
the  teeth  of  some  species  are  valued  by  some  peoples;  ribs  and  other 
long  bones  are  sometimes  used  by  semi-civilized  peoples  in  house- 
building; the  hides  of  porpoises  are  made  into  leather.  Altogether 
this  small  group  of  large  animals  has  a  verv  considerable  economic 
value. 


REFERENCES       ; 
GENERAL  WORKS 

1.  Barrows,  F.  W.     Economic  Zoology.     School  Science,  May-  June,  1903. 

2.  Brehms  Thierleben,  n  vols.    Leipzig  and  Vienna,  1914. 

3.  Cambridge  Natural  History,  n  vols.     New  York,  1909. 

4.  Daugherty,  L.  S.  &  M.  C.     Economic  Zoology.     Phila.,  1912. 

5.  Encyclopedias  and  other  general  references. 

6.  Hegner,  R.     College  Zoology.     New  York,  1912. 

7.  Hornaday,  W.  T.     The  American  Natural  History.     New  York,  1906. 

8.  Jordan,  D.  S.,  Kellogg,  V.  L.,  &  Heath,  H.     Animal  Studies.     New  York,  1911. 

9.  Kellogg,  V.  L.     Animals  and  Man.     New  York,  1911. 

10.  Kellogg,  V.  L.,  &  Doane,  R.  W.     Economic  Zoology  &  Entomology.     New 
York,  1915. 

11.  The  New  Natural  History  (Lydekker),  6  vols.     New  York,  1901. 

12.  Osborn,  Herbert.     Economic  Zoology.     New  York,  1908. 

13.  Parker,  T.  J.,  &  Haswell,  W.  A.     Textbook  of  Zoology,  2  vols.     New  York, 
1897. 

PROTOZOA 

14.  Bagshaw,  A.  G.     Recent  Advances  in  our  Knowledge  of  Sleeping  Sickness. 
Lancet,  II,  pp.  1193-97,  1909. 

15.  Braun.     Die  thierischen  Parasiten  des  Menchen,  Wurzburg,  1903.     (Trans., 
New  York,  1909.) 

16.  Calkins,  G.  N.     Protozoology.     New  York,  1909. 

17.  Clarke,  J.  J.     Protozoa  and  Disease,  Pt.  i,  London,  1903;  Pt.  2,  London,  1908. 
170.  Coplin,  W.  M.     Manual  of  Pathology.     Phila.,  1913. 

1  8.  Craig,  C.  F.     The  Malarial  Fevers,  Hemoglobinuric  Fever  arid  the  Blood 
Protozoa  of  Man.     New  York,  1909. 

19.  Doane,  R.  W.     Insects  and  Disease.     New  York,  1910. 

20.  Doflein.    Lehrbuch  der  Protozoenkunde.     Jena,  1909. 

21.  Dutton,  J.  E.,  Todd,  J.  L.,  &  Harrington,  J.  W.  B.     Trypanosome  Transmission 
Experiments.     Amer.  Trop.  Med.  &  Parasit,  Vol.  I,  No.  2,  1907. 

22.  Francis.     An    Experimental   Investigation   of    Trypanosoma  Lewisii.     Bull. 
No.  ii,  U.  S.  Hygienic  Lab.,  1903. 

23.  Jordan,  O.  E.     Textbook  of  General  Bacteriology.     Phila.  &  London,  1914. 

24.  Kolle,  W.,  &  Wassermann,  A.     Handbuch  der  pathogenen  mikroorganism, 


25.  Laveran  &  Mesnil.     Trypanosomes.     (Trans,  by  Nabarro,  Chicago,  1907.) 

286 


REFERENCES  287 

26.  Minchen,  E.  A.     Protozoa,  In  Albutt  &  Rollston's  System  of  Medicine,  II, 
1907. 

27.  MacCallum,  W.  G.     Textbook  of  Pathology.     Phila.,  1916. 

28.  Novy,  T.  G.,  McNeal,  M.  S.,  &  Torry,  H.  M.     The  Trypanosomes  of  Mos- 
quitoes and  Other  Insects.     Jour.  Infec.  Dis.,  IV,  1907. 

29.  Osier,  Sir.  Wm.     Modern  Medicine,  Vol.  I,  Pt.  VI,  1907. 

30.  Ross,  Ronald.     Malarial  Fever,  Its  Cause,  Prevention  &  Treatment.    London, 
1912. 

31.  Roubaud.    La  Glossina  palpalis;  sa  biology,  son  role  dans  1'etiologie  des  Try- 
panosomiasis.     Paris,  1909. 

32.  Stitt,  E.  R.     Practical  Bacteriology,  Blood  Work  and  Animal  Parasitology, 
5th  edition.     Philadelphia  and  London,  1918. 

32a.  Various  Medical  Works. 

33.  Ziegler,  E.     General  Pathology.      (Trans,  by  A.  S.  Warthen,  New  York,  1903.) 

PORIFERA 

34.  Cobb,  J.  N.     The  Sponge  Fishery  of  Florida  in  1900.     Report  of  U.  S.  Fish 
Com.,  1902. 

35.  Duerden,  J.  E.     The  Marine  Resources  of  the  British  West  Indies.     West 
Indian  Bulletin  of  the  Imperial  Dept.  of  Agr.  for  the  West  Indies,  1901. 

36.  Encyclopedia  Americana.     Sponges,  by  J.  P.  Moore. 

37.  Moore,  J.  P.     Report  on  Sponge  Culture,  1902. 

38.  Rathbun,  R.     Fisheries  Industries  of  the  United  States,  1884. 

CCELENTERATES 

39.  Encyclopedias  and  various  textbooks  of  zoology. 

40.  Simmons,  P.  L.     The  Animal  Food  Resources  of  the  Different  Nations.      N.  Y., 
1885. 

ECHINODERMS 

41.  Brooks,  W.  K.     The  Oyster.     Baltimore,  1905. 

42.  Duerden,  J.  E.     See  references  for  Porifera. 

43.  Kellogg,  J.  L.     The  Shellfish  Industries.     New  York,  1910. 

44.  Simmons,  P.  L.     See  references  for  Ccelenterates. 

CESTODES 

45.  Braun.     See  Protozoa. 

46.  MacCallum.     See  Protozoa. 

47.  Nuttall.     The    Poisons  given  off  by  Parasitic  Worms  in  Man  &  Animals. 
Amer.  Nat.,  1899. 

48.  Osier,  Sir.  Wm.     Principles  &  Practice  of  Medicine.     New  York,  1914. 

49.  Stiles,  C.  W.     Cestode  Parasites  of  Man.     Bull.  25  and  28,  U.  S.  Hygienic 
Laboratory. 

50.  Stiles  &  Hassall.     The  Inspection  of  Meats  for  Animal  Parasites.     Bull.  19, 
U.  S.  Dept.  of  Agriculture. 


288  ECONOMIC  ZOOLOGY 

Soa.  Ibid.     Index  Catalog  of  Medical  &  Veterinary  Zoology.     Washington,  1908. 

51.  Stitt.     See  Protozoa. 

52.  Wilson.     Bothriocephalus  latus  (U.  S.).     Amer.  Jour.  Med.  Sc.  (Lit.),  1902. 

53.  Ziegler,  E.     See  Protozoa. 

TREMATODES 

\ 

54.  Cecil.     Proceed.  N.  Y.  Pathological  Soc.,Vol.  X,  p.  206,  1910-11. 

55.  MacCallum.     See  Protozoa. 

56.  Stiles.     Pulmonary     Distomatosis.     Proc.    Pathological     Soc.     Phila.,    Vol. 
IV,  p.  61,  1901. 

560.  Stitt.     See  Protozoa. 

57.  Ward.     Trematoda.     Reference  Handbook  of  Medical  Science,  1903. 

58.  Ziegler,  E.     See  Protozoa. 

HOOKWORM 

59.  Menche.     Anchylostomiasis.     Zeitschr.  f.  klin.  Med.,  Vol.  VI. 

60.  Rockefeller  Hookworm  Commission,  Reports  of. 

61.  Stiles,  C.  W.    Hookworm  Disease.    Bull.  10,  Hygienic  Lab.    Washington,  1903. 

62.  Ibid.     Hookworm  Disease.     Pub.  Health  Bull.  32,  Washington,  1910. 
620.  Stitt.     Tropical  Diseases,  2d  edition.     Philadelphia,  1917. 

63.  Various  Textbooks  of  Pathology. 

64.  Whipple.     Hookworm  Disease.     Jour.  Exp.  Medicine,  Vol.  XI,  No.  2,  1909. 

TRICHINIASIS 

65.  Chatin.    La  trichine  et  la  trichinose.     Paris,  1883. 

66.  Herrick  &  Janeway.     Arch.  Internal  Medicine,  Vol.  Ill,  p.  263,  1909. 

67.  Stiles,  C.  W.     Trichinosis  in  Germany.     Bull.  30,  U.  S.  Bureau  of  Animal 
Industry,  1901. 

68.  Thompson.     Trichiniasis.     American  Journal  Medical   Science,   Aug.,   1910. 

69.  Various  Pathologies. 

70.  Williams.     The    Frequency   of   Trichinosis  in  the  U.  S.  Jour.  Medical  Re- 
search, 1901. 

ASCARIS,  FlLARIA,  ETC. 

71.  Francis.     Guinea- worm  Disease.     Amer.  Medicine,  Oct.  26,  1901. 

72.  James.     On  the  Metamorphosis  of  Filaria  sanguinis  in  Mosquitoes.     British 
Med.  Jour.,  Vol.  II,  1900. 

73.  Looss.     Mense's  Handb.  d.  Tropenkrankheiten,  Vol.  I,  pp.  77-202,  1905. 

74.  Lothrop  &  Pratt.     Two  Cases  of  Filariasis.     Amer.  Jour.  Med.  Sc.,  Vol.  CXX, 
1900. 

75.  Sonsino.     The  Life-history  of  Filaria  Bancrofti.     British  Med.  Jour.,  Vol.  I, 
1900. 

7$a.  Stitt.     See  Protozoa. 

76.  Various  Pathologies. 

77.  Whyte.     Filaria.    Jour.  Tropical  Med.  &  Hyg.,  June  15,  1909. 

ANNULATA 

78.  Encyclopedias  and  various  zoological  and  medical  works. 


REFERENCES  .  289 

MOLLUSCA 

79.  Brooks,  W.  K.     The  Oyster.     Baltimore,  1905. 

80.  Dakin,  W.  S.     Pearls.     New  York  and  London,  1913. 

81.  Duerden,  J.  E.     See  references  for  Porifera. 

82.  Field,  I.  A.     The  Food  Value  of  Sea  Mussels.     Bull.  Bur.  Fisheries,  Vol.  XXIX, 
1911. 

83.  Grave,  C.     History  of  Oyster  Production  in  Maryland,  1810-1912.     Proc.  of 
3d  Annual  Convention  of  the  Nat.  Assoc.  of  Shellfish  Commissioners. 

84.  Kellogg,  J.  L.     The  Shellfish  Industries.     New  York,  1910. 

85.  Reports  of  the  Shellfish  Commission  of  Maryland.     Baltimore. 

86.  Rust,  E.  W.     Edible  Snails.     U.  S.  Dept.  Agr.  Yearbook,  1914. 

87.  Sigerfoos,  C.  P.     Natural  History,  Organization,  and  Late  Development  of 
the  Teredinea  or  Ship- worms.     Bull.  U.  S.  Bur.  Fisheries,  Vol.  17,  1907. 

88.  Stiles,  G.  W.     The  Value  of  the  Shellfish  Industry  and  the  Protection  of 
Oysters  from  Sewage  Contamination.     Yearbook  Dept.  Agr.,  1910. 

89.  Various  Government  publications,  encyclopedias,  etc. 

ARTHROPODS 

90.  Andrews,  E.  A.     The  Future  of  the  Crayfish  Industry.     Science,  1906. 

91.  Bishop,  F.  C.     Fleas.     U.  S.  Bur.  Entomology,  Bull.  248,  1915. 

92.  Cambridge  Natural  History  and  similar  works. 

93.  Comstock.     The  Spider  Book. 

94.  Duerden,  J.  E.     See  references  for  Porifera. 

95.  Felt,  E.  P.     Mosquito  Control.     Bull.  104,  N.  Y.  State  Museum,  1905. 

96.  Fisher,  A.  K.     Crayfish  as  Crop  Destroyers.     Yearbook    U.  S.  Dept.  Agr., 
1911. 

97.  Herrick,  F.  H.     Natural  History  of  the  American  Lobster.     Bull.  Bur.  Fish- 
eries, 1911. 

98.  Howard,  L.  O.     Mosquitoes  of  the  U.  S.     Bull.  25,  Div.  Entomology,  U.  S. 
Dept.  Agr.,  1900. 

99.  Ibid.     Insect  Book.     New  York,  1901. 

100.  Ibid.     House  Flies.     Farmers'  Bull.  679,  U.  S.  Dept.  Agr.,  1915. 

10 1.  Ibid.     Economic  Loss  to  the  People  of  the  United  States  Through  Insects  that 
Carry  Disease.     Bull.  78  (revised)  Bur.  Entomol.,  U.  S.  Dept.  Agr.,  1909. 

102.  Kellogg,  V.  L.     Spider  Poison.     Jour.  Parasitology,  Vol.  I,  1915. 

103.  Marlatt,  C.  L.     House  Ants.     Farmers'  Bull.  740,  U.  S.  Dept.  Agr.,  1916. 

104.  Ibid.     The  Bedbug.     Farmers'  Bull.  754,  U.  S.  Dept.  Agr.,  1916. 

105.  Ibid.     Cockroaches.     Farmers'  Bull.  658,  U.  S.  Dept.  Agr.,  1915. 

106.  Synder,  T.  E.     Termites,  or  "  White  Ants  "  in  the  United  States,  their  Damage 
and  Methods  of  Prevention.     Bull.  333,  Bur.  Entomol.,  U.  S.  Dept.  Agr.,  1916. 

107.  Various  Government  Reports  and  general  works. 

FISHES 

1 08.  Cunningham.     Marketable  Marine  Fishes.     New  York,  1896. 

109.  Duerden.     See  Porifera. 

19 


2  90  ECONOMIC  ZOOLOGY 

no.  Goode,  G.  B.     Fisheries  Industries  of  U.  S.,  1884-87. 
in.  Ibid.     American  Fishes. 

112.  Hall.     Herring  Fisheries  of  Passamaquoddy  Bay.     Rep.  U.  S.  Fish  Com.,  1896. 

113.  Jordan,  Everman,  Bean  &  Others.     Various  works. 

114.  Manual  of  Fish  Culture.     Report  U.  S.  Fish  Com.,  1897. 

115.  Mclntosh.     Resources  of  the  Sea,  1899. 

1 1 6.  Mowbray,  L.  L.     On  Poisonous  Fish  &  Fish  Poisoning.     N.  Y.  Zool.  Soc. 
Bull.,  Nov.,  1916.     Also  Copeia,  Sept.  24,  1917. 

117.  Simmons.     Commercial  Products  of  the  Sea,  1883. 

118.  Smith.     The  French  Sardine  Industry,  1901. 

119.  Ibid.     Alewife  Fisheries  of  U.  S.     Report  U.  S.  Fish  Com.,  1898. 

120.  Stevenson.     Preservation  of  Fisheries  Products  for  Food.     Bull.  U.  S.  Fish 
Com.,  1898. 

121.  Ibid.     The  Shad  Fisheries  of  the  Atlantic  Coast.     Report  U.  S.  Fish  Com., 
1899. 

122.  Townsend,  C.  H.     The  Cultivation  of  Fishes  in  Natural  and  Artificial  Ponds. 
In  nth  Annual  Report  of  N.  Y.  Zoological  Soc.,  1916. 

AMPHIBIA 

123.  Cambridge  Natural  History  and  similar  works. 

124.  Chamberlain,  F.  M.     Notes  on  the  Edible  Frogs  of  the  U.  S.     Report  of  the 
Commissioner,  U.  S.  Fish  Com.,  1897. 

125.  Dickerson,  Mary  C.     The  Frog  Book.     New  York,  1906. 

126.  Kirkland,  H.  A.     The  Habits  of  the  American  Toad.    Hatch  Expt.  Sta.  Bull. 
46,  1897. 

127.  Surface,  H.  A.     First  Report  on  the  Economic  Features  of  the  Amphibians  of 
Penna.     Zool.  Bull.  Penna.  Dept.  Agr.,  Harrisburg,  May-July,  1913. 

REPTILES 

128.  Cambridge  Natural  History  and  similar  works. 

129.  Duerden,  J.  E.     See  references  for  Porifera. 

130.  Ditmars,  R.  L.     The  Reptile  Book.     New  York,  1907. 

131.  Ibid.     Reptiles  of  the  World.     New  York,  1910. 

132.  Reese,  A.  M.     The  Alligator  and  its  Allies.     New  York,  1915. 

133.  Ibid.     Reptiles  as  Food.     Scientific  Monthly,  Nov.,  1917. 

134.  Smith,  H.  M.     Notes  on  the  Alligator  Industry.     Bull.  U.  S.  Fish  Com., 
Vol.  2,  1891. 

135.  Stevenson,  C.  W.     Utilization  of  the  Skins  of  Aquatic  Animals;  Leather  from 
Alligator  Skins.     Report  of  Commissioner  of  Fish  &  Fisheries  for  1902,  pub. 
1904. 

136.  Surface,  H.  A.     First  Report  on  the  Economic  Features  of  the  Turtles  of  Penna. 
Zool.  Bull,  of  the  Dept.  of  Agr.  of  Penna.     Harrisburg,  Aug.-Sept.,  1908. 

137.  Ibid.     The  Lizards  of  Pennsylvania.     Ibid.,  Dec.,  1907. 


REFERENCES  2QI 

BIRDS 

138.  Beal,  F.  E.  L.  &  Others.     Common  Birds  of  S.  E.  United  States  in  Relation  to 
Agriculture.     Farmers'  Bull.  755,  U.  S.  Dept.  Agr.,  1916. 

139.  Chapman,  F.  M.     Birds  of  Eastern  North  America.     New  York,  1910. 

140.  Ibid.     Color  Key  to  North  American  Birds.     New  York,  1903. 

141.  Dearborn,  N.     Bird  Houses  and  How  to  Build  Them.     Farmers'  Bull.  609, 
U.  S.  Dept.  Agr.,  1914. 

142.  Duerden,  J.  E.    The  Plumage  of  the  Ostrich.     Smithsonian  Annual  Report, 
1910. 

143.  Fisher,  A.  K.     Economic  Value  of  Predaceous  Birds  and  Mammals.    Yearbook 
of  the  U.  S.  Dept.  Agr.,  1908. 

144.  Forbush,  E.  H.     Useful  Birds  and  Their  Protection.     Boston,  1907. 

145.  Henshaw,  H.  W.     Does  it  Pay  the  Farmer  to  Protect  Birds?    Yearbook  of 
the  U.  S.  Dept.  Agr.,  1907. 

146.  Hornaday,  W.  T.     Wild  Life  Conservation  in  Theory  and  Practice.     New 
Haven,  1914. 

147.  Judd,  S.  D.     The  Relation  of  Sparrows  to  Agriculture.     Bull.  15,  Biological 
Survey,  U.  S.  Dept.  Agr.,  1901. 

1470.  Kalmbach,  E.  R.     The  Crow  and  Its  Relation  to  Man.     Bull  621,  U.  S. 
Dept.  Agr.,  1918. 

148.  McAtee,  W.  L.      How  to  Attract  Birds  in  Northwestern  United  States. 
Farmers'  Bull.  760,  U.  S.  Dept.  Agr.,  1916. 

149.  Mosenthal  and  Harting.     Ostriches  and  Ostrich  Farming,  1878. 

150.  Pickrell,  W.     Ostrich  Farming  in  Arizona.     Yearbook  U.  S.  Dept.  Agr.,  1905. 

151.  Reed,  C.  A.     Bird  Guides.     New  York,  1912. 

152.  Surface,  H.  A.     Bird  Preservation.    Zool.  Bull.  Penna.,  Dept.  Agr.,  Feb.,  1908. 

153.  Ibid.     Some  Pennsylvania  Birds  and  Their  Economic  Value.     Ibid.,  Sept.- 
Nov.,  1913;  Jan.-Mar.  &  May-June,  1914. 

154.  U.  S.  Dept.  Agr.  and  other  Government  reports. 

MAMMALS 

155.  Beddard,  F.  E.     A  Book  of  Whales.     New  York,  1900. 

156.  Duerden,  J.  E.     See  references  for  Porifera. 

157.  Fisher,  A.  K.     See  reference  under  Birds. 

158.  Grosvenor,  R.  D.     Reindeer  in  Alaska.     Smithsonian  Report,  1903. 

159.  Heath,  H.     Special  Investigation  of  the  Alaska  Fur-Seal  Rookeries.  U.   S. 
Bureau  of  Fisheries,  Document,  748,  1910. 

1 60.  Hornaday,  W.  T.     See  reference  under  Birds. 

161.  Jackson,  S.    Introduction  of  Domesticated  Reindeer  into  Alaska.     U.   S. 
Bureau  of  Education,  No.  215,  1894. 

162.  Jones,  J.  W.     Fur  Farming  in   Canada.     Commission  of  Conservation  of 
Canada,  Montreal,  1913. 

163.  Jordan,  D.  S.  and  Others.     Report  of  the  Fur-Seal  Investigation,  3  vols., 
Washington,  1896-98. 


2Q2  ECONOMIC   ZOOLOGY 

164.  Lantz,  D.  E.     Directions  for  Destroying  Pocket  Gophers.     Circular  52,  U.  S. 
Biol.  Survey,  1908. 

165.  Ibid.     Pocket  Gophers  as  Enemies  of  Trees.     Yearbook,  U.  S.  Dept.  Agr., 
1909. 

166.  Ibid.     The  Brown  Rat  in  the  U.  S.  Bull.  33,  U.  S.  Biol.  Survey,  1909. 

167.  Ibid.     Field  Mice  as  Farm  and  Orchard  Pests.     Farmers'  Bull.  670,  U.   S. 
Dept.  Agr.,  1915. 

168.  Ibid.     How  to  Destroy  Rats.     Farmers'  Bull.      369,  U.  S.  Dept.  Agr.,  1916. 

169.  Ibid.     Destroying  Rodent  Pests  on  the  Farm.     Yearbook,  U.  S.  Dept.  Agr., 
1916. 

170.  Ibid.     House  Rats  &  Mice.     Farmers'  Bull.  896,  U.  S.  Dept.  Agr.,  1917. 

171.  Ibid.     Raising  Deer  &  Other  Large  Game  Animals  in  the  U.  S.     Bull.  36,  U. 
S.  Biol.  Survey,  1910. 

172.  Ibid.     Economic  Value  of  N.  A.  Skunks.     Farmers'  Bull.  587,  U.  S.  Dept., 
Agr.,  1914. 

173.  Ibid.     Raising  Guinea  Pigs.     Ibid.,  No.  525,  1913. 

174.  Ibid.     Cottontail  Rabbits  in  Relation  to  Trees  &  Farm  Crops.     Ibid.,  702, 1916. 

175.  Ibid.     The  Muskrat  as  a  Fur  Bearer,  with  Notes  on  Its  Use  as  Food.    Ibid., 
No.  869,  1917. 

176.  Ibid.    Laws  Relating  to  Fur-Bearing  Animals.     Ibid.,  No.  911,  1917. 

177.  Lembkey,  W.  I.     The  Fur-Seal  Fisheries  in  Alaska  in  1910.     Bureau  of  Fish- 
eries Document,  749,  1911. 

178.  MarshaU,  F.  H.  Heller,  L.  L.,  &  McWhorter,  F.  H.  Karakul  Sheep.     Yearbook 
of  the  U.  S.  Dept.  Agr.,  1915. 

179.  Merriam,  C.  H.     The  California  Ground  Squirrel.     Circular  76,  U.  S.  Biol. 
Surv.,  1910. 

180.  Nelson,  E.  W.     The  Rat  Pest.     Nat.  Geographic  Mag.,  July,  1917. 

181.  Osgood,  W.  H.     The  Game  Resources  of  Alaska.     Yearbook  U.  S.  Dept.  Agr., 
1907. 

182.  Parker,  G.  H.     The  Fur-Seals  of  the  Pribilof  Islands.     Scientific  Month., 
May,  1917. 

183.  Rabot,  C.    Whale  Fisheries  of  the  World.     Smithsonian  Report  for  1913. 

184.  Scheffer,  T.  H.     The  Common  Moles  of  the  Eastern  United  States.     Farmers' 
Bull.  583,  U.  S.  Dept.  Agr.,  1917. 

185.  Stevenson,  C.  H.     Whalebone  and  its  Production.     Doc.  626,  U.  S.  Fish  Com. 
1907. 

1 86.  Surface,  H.  A.     Zoological  Conservation.     Zool.  Bull.  Penna.  Dept.  Agr. 
Nov.,  1911. 

187.  True,  F.  W.     The  Whalebone  Whales  of  the  Western  North  Atlantic.     Smith- 
sonian Contributions  to  Knowledge,  No.  1414,  1904. 


INDEX 


Abalone,  58 
Acarina,  82,  83 
Accipiter  atricapillus,  192 
cooperi,  192,  193 
velox,  192 

Acipencer  huss,  see  Sturgeon,  117 
Acorn  barnacle,  70 
Actinozoa,  16 
African  elephant,  265,  266 

ostrich,  180-84 
Age  of  reptiles,  135 
Agramonte,  Dr.  A.,  9 
Aigrets,  186 
Alaskan  fur-seal,  224 
Alces  americanus,  see  Moose. 
Aleution  Islands,  224 
Alfalfa,  destruction  of,  by  meadow  mice, 

247,  248 

poisoned,  for  rodents,  249-50 
Alligator,  and  cane  rats  and  muskrats, 

171 

eggs  as  food,  175 
as  food,  "175-76 
hides,  first  use  of,  170 
numbers  taken,  1 70 
output  of  tanneries,  171 
preparation  of,  172 
sizes  used,  171 
value  of,  to  hunter,  171 
value  tanned,  172 
where  collected,  170 
leather,  demand  for,  in  1918,  172 

imitation  of,  172 
methods  of  cooking,  176 

of  hunting,  172,  174 
skins  of,  173 

reduction  in  numbers  of,  171 


Alligator,  trade  in  teeth,  etc.,  174-75 

wanton  destruction  of,  171 
"Alligator,"  see  Cryptobranchus. 
Allolobophora,  40 
Alpaca,  domestication  of,  267 

as  wool  producer,  267 
Ambergris,  formation  of,  285 

use  and  value  of,  285 
Amblystoma  punctatum,  126 
Ameba,  i 

Amebic  dysentery,  2 
American  Bison  Society,  268 
American  Goshawk,  192 
Amniota,  135 
Amphibia,  108,  123-34 

characteristics  of,  123 

classification  of,  124 

confused  with  reptiles,  123 

extinct,  123-24 

hibernation  of,  124 

means  of  self-protection,  125 

number  of  species,  123 
Amphineura,  45,  66,  76 
Amphioxus,  anatomy  of,  108 
Ancistrodon  contortrix,  159-60 

piscivorus,  158,  159 
Anclote  Key  sponges,  13 
Ankylostoma,  duodenale,  33 
Annelids,  40 

classification  of,  40 
Annulata,  26,  40 
Anodon,  44 
Anopheles,  6,  83,  84,  86,  87 

characteristics  of,  84 
Antarctic  whaling,  280 
Anteater,  260-61 
Anthozoa,  16,  17 
Antivenin,  157 
Anti venom  sera,  157 


293 


294 


INDEX 


Anura,  124,  126-27 

families  of,  127 
Apes,  262 

Apiaries  of  California,  102 
Apoda,  124,  126 
Appalachicola  sponges,  13 
Apteryx  australis,  see  Kiwi,  180 
Arachnida,  70,  79 

characteristics  of,  71 
Archaeopteryx  lithographica,  178-79 
Archaeornithes,  178 
Ardea  egretta,  186-87 
Aristotle's  lantern,  21 
Armadillo,  260-62 

destruction  of,  262 

food  of,  262 

as  food,  262 

habits,  262 

Arsenic,  white,  as  rat  poison,  241 
Arthropoda,  68 

classification  of,  68 

number  of  species,  68 
Artiodactyla,  263-64 
Ascaris  lumbricoides,  31-33 
Asia  Minor,  sponges  of,  12 
Aspidonectes  spinifer,  146 
Ass,  264 

Astacus,  see  Crayfish. 
Asteroidea,  20,  24 
Astracan,  215 
Atoll,  1 8,  19 
Audubon  Society,  178,  186 

organization  of,  200 
Aves,  177,  204,  see  Birds. 
Aviculidae,  61 


Babesia,  4 

Bacteria  on  fly's  wing,  93 
Bactrian  camel,  266 
Badgers  and  ground  squirrels,  254 
Bahama  Islands,  sponges  of,  12 
Balaena  mysticetus,  276 
Balaenoptera  musculus,  277,  282 
physalus,  see  Finback  whale. 
Balanus,  see  Acorn  barnacle,  70 


Baleen  or  whalebone,  277 

bundles  of,  284 

chief  factories,  285 

from  one  animal,  282 

past  and  present  values,  285 

ports  of  receipt,  285 

removal  from  whale,  282 

size  of  slabs,  282-84 

substitutes  for,  285 

whales  producing,  281 
Barbados,  sea-eggs  of,  24 
Barbary  sponges,  12 
Barium  carbonate  as  rat  poison,  241 
Barnacles,  69 
Barracuda,  113 

Barren-ground  caribou,  272-73 
Basket  fish,  22 
Bat,  brown,  211 

food  of,  210 

hibernation  of,  210 

little  brown,  210 

number  of  species,  210 

red,  211 

shelters  for,  210 

size  of,  210 

tactile  sense  of,  210 

vampire,  211 
Batrachia,  see  Amphibia. 
Bdellostoma,  108-10 
Beaded  lizards,  see  Lizard,  150 
Bear,  172 

family,  212 

-goat  skin,  221 

skins,  222 
Beaver,  221,  223 

as  food,  260 

skins,  213 
Beche-de-mer,  25 
Bedbug  and  kala-azar,  10 

methods  of  control,  102 
Beebe,  C.  W.,  211 
Beechey  ground    squirrel,  see   Ground 

squirrel. 

Beef  tapeworm,  27,  28 
Bee  keeping,  time  and  place  of  origin, 
103 


INDEX 


295 


Bee  keeping,  trees,  103 
Bees- wax,  production  of,  103 
Beetle  larvae  as  food,  103 
Belly  skin  of  alligator,  172 
Benzine  for  moths,  102 
Bilibed  prison  and  hookworm,  36 
Biological  Survey,  178,  190,  212 
Birds,  relation  to  agriculture,  189-97 

altricial,  178 

bag  limits  of,  200 

characteristics  of,  177-78 

classification  of,  178 

closed  seasons  for,  200 

collection  of  eggs,  200 

decrease  in  numbers  of,  197 

destroyed  by  cats,  197 
by  dogs,  198 
by  foreigners,  197 
by  rats,  etc.,  198 

destroyers  of  insects,  189-91 
of  rodent  pests,  191-94 

eggs  of,  177 
as  food,  184 

enemies  of,  197 

feeding  boxes,  203-04 

as  food,  184 

food,  determination  of,  190 
shelf,  202 

fruits  and  berries,  202 

houses,  199 

law  in  Pa.,  193-94 

law  treaty  with  Canada,  199 

lectures  on,  200 

list  of  those  protected  in  U.  S.  A., 
199-200 

natural  enemies,  197 

nests,  edible,  185 

number  of  species,  178 

as  ornaments,  186,  200 

Paradise,  186 

precocious,  178 

preserves,  203-04 

protection  of,  197-204 

as  scavengers,  186-87 

shooting  of,  198 

study  of  feeding  habits,  190 


Birds,  study  of  stomach  contents,  190 

supplying  food  for,  202 

teeth  and  vertebrae,  177 
Bishop  Museum,  Honolulu,  186 
Bison,  226 

American,  267-68 

preserves,  267 

wanton  destruction  of,  267 
Bivalves,  see  Lamellibranchs. 
Black  caiman,  176 

death,  see  Bubonic  plague. 

fox,  216 

value  of  breeders,  217 

marten  skin,  222 

rat,  229 

vulture,  188 

widow  spider,  see  Spider. 
Blackbirds  or  grackles,  195-96 
Blackheads,  82 
Black  snakes  as  ratters,  251 
Bladder- worms,  27,  28 
Blubber  of  whale,  281 
Blue  jay,  195 

Bobcats  and  ground  squirrels,  254 
Bombyx  mori,  see  Silk  worm. 
Bony  fishes,  113 
Booby  eggs,  184 
Boring  sponges,  14 
Bot-fly  of  cattle,  91 

of  horse,  90 

of  man,  91 

Box  tortoise  as  food,  137 
Bradypodidae,  see  Sloths. 
Breakbone  fever,  10 
Brittle-stars,  22,  24,  25 
Brooks,  W.  K.,  45,  47,  61 
Brown  bat,  211 

rat,  229-44 
Bubo  virginianus,  191 
Bubonic  plague,  control  of,  228 

deaths  from,  228 

history  of,  228 
Buddhists,  6r 
Buffalo  robes,  267 
Bufo  lentiginosus  americanus,  132 
Bufonidae,  species  of,  132 


296 


INDEX 


Bullfrog,  128-29 

Bull  seals,  224 

Bureau  of  Animal  Industry,  34 

Bureau  of  Education,  272-73 

Bureau  of  Fisheries,  14,  115,  117,  118, 

119,  120,  122 
Burpee,  A.  M.,  140 
Buteo  borealis,  192 

lineatus,  192 

"Button"  of  rattlesnake,  162 
Buzzards  and  poisoned  ground  squirrels, 
254 


Caiman,  136,  176 

niger,  176 

California  ground  squirrel,  see  Squirrel. 
Callinectes,  76 
Callorhinus  alascanus,  223 
Calmette,  A.,  157 
Cambarus,  see  Crayfish. 
Cambrian  sponges,  12 
Camel,  264 

in  America,  267 

domestication  of,  267 

flesh  of  hump,  267 

milk  and  flesh  of,  as  food,  267 

species  of,  266 

speed  and  strength  of,  267 

storage    of    water    in   stomach   of, 

266 

Camelidae,  267 
Camel's  hair  cloth,  267 
Camelus,  see  Camel. 
Cameo  shell,  59 
Canal  zone,  fevers  at,  9 
Canals  of  sponges,  n 
Cancer  irroratus,  77 
Canidae,  212 

Carbon  bisulphid  for  rodent  pests,  243, 
254,  258,  259 

monoxid  for  destruction  of  jats,  241 
Carcharodon,  see  Great  white  shark. 
Caribou,  see  Reindeer. 
Carinatae,  178 


Carnivora,  211 

canine  teeth  of,  211 

as  destroyers  of  rodent  pests,  251 

as  food,  222 

food  of,  2 it 

losses  by  predatory,  212 

predatory,  campaign  against,  212 

teeth  of,  211,  212 

vera  or  fissipedia,  212 
Carrion  crows,  188 
Carroll,  Dr.  James,  9 
Carybdea  marsupialis,  16 
Cassis,  see  Cameo  shell. 
Castor  canadensis,  223,  224 
Castoridae,  228 
Catharista  atrata,  188 
Cathartes    aura,   see   Turkey   buzzard. 

188,  189 
Cat  family,  212 

skins,  222 
Cats  as  destroyers  of  birds,  197 

and  dogs,  destruction  of,  200 
Cattle,  264 
Caudata,  124-26 
Caviare  from  sturgeon,  118 
Centipedes,  69,  78 

as  food,  78 

poisonous  to  man,  78,  79 
Central  America,  sponges  of,  12 
Cephalochorda,  107 
Cephalopoda,  45,  65-67 
Cercaria,  29 

Cervus,  americanus;  canadensis,  see  Elk. 
Cestoda,  26-28 
Cetacea,  274-85 

classification  of,  274,  276 
Ceylon  pearl  fisheries,  62 
Chaetopoda,  40 
Chapman,  F.  M.,  193 
Chelone  mydas,  see  Green  turtle. 
Chelonia,  135-48 

characteristics  of,  135-36 

as  food,  136-37 

imbricata,  148 

for  scientific  purposes,  147 
Chelydra  serpentina,  144 


INDEX 


2Q7 


Chiggers,  destruction  of,  82 

Chills,  6,  7 

Chimpanzee,  262 

Chincha  Island,  guano  of,  86-87 

Chioptera,  210 

Chitons,  see  Amphineura,  45,  60 

Chlorine  for  destruction  of  rats,  241 

Choleopus  didactylus,  260 

Cholera  and  fleas,  92 

Chorda ta,  characteristics  of,  107 

Cistudo  (Terrapene)  Carolina,  147 

Citellus  beecheyi,  see  Ground  squirrel. 

Clam,  44 

bakes,  53 

chowder,  53 

culture,  54 
Clean  cultivation  to  prevent  field  mice, 

250 
Clothes  moths,  100-02 

case-making,  101 

distribution- of ,  100 

life-history  of,  100 

protection  against,  101,  102 
Clupea  cacruteus,  116 

harengus,  see  Herring. 

pilchardus,  see  Sardine. 
Clupeidae,  see  Herring. 
Cobra,  153,  156 
Cod,  breeding  habits  of,  116 

drying,  116 

eggs,  116 

fisheries  of  Iceland  and  Newfound- 
land, 116 

-liver  oil,  1 13 

size  and  importance,  116 
Ccelenterata,  15 
Coendidae  (Hystricidae),  228 
Cold  storage  and  moths,  102 
Collette,  19 
Coluber  emoryi,  116 

gattatus,  1 66 

obsoletus,  1 66,  167 

yulpinus,  166 

Columbia  River  salmon,  116-17 
Comb  jellies,  16 
Common  swift,  151 


Comstock,  C.  J.  H.,  80 
Condor,  see  California  vulture,  189 
Coney,  see  Hyracoidea. 
Copperhead,  see  Snake. 
Coral,  17 

fisheries,  19 

islands,  18 

limestone,  18 

precious,  occurrence  of,  18,  19 
use  of,  1 8,  19 
value  of,  19 

reefs,  17 

snakes,  153,  154 
bite  of,  154 
characteristics  of,  154 
distinguished   from   scarlet  king 

snake,  154 

Cotton  mouth,  see  Snake. 
Cottontail  rabbits,  254,  255 
Coureurs  des  bois,  213 
Cowries,  60 
Cow  seals,  224 
Cox,  Alvin,  59 
Coyote,  212,  222 

and  field  mice,  251 

and  ground  squirrels,  254 
Crab,  69 

cooking  of,  77 

exhaustion  of  supply,  77 

hard-shell,  76-77 

laws  for  protection  of,  77 

soft-shell,  76,  77 

use  for  food,  76 
Crawfish,  see  Crayfish. 
Crayfish,  68,  69,  71,  74-76 

canning  of,  75 

for  chicken  feed,  88 

damage  to  crops,  75-76 

habits  and  cultivation  of,  75 

methods  and  cost  of  extermination, 
76 

number  per  acre,  76 
sold,  74,  75 

poisons  for,  76 

use  as  food,  74,  75 
Crete,  sponges  of,  12 


298 


INDEX 


Crinoidea,  22,  25 
Crinoid  deposits,  24 
Crocodile,  136 

African,  176 

salt  water,  176 
Crocodilia,  170 

characteristics  of,  136 

dangerous  to  man,  176 
Crocodilus  niloticus,  176 

porosus,  176 

Crotalus  adamanteus,  161,  162 
Crow,  American,  195 

fish,  195 

Crows  and  jays  as  bird  destroyers,  190 
Crustacea,  68,  71 

characteristics  of,  68,  69 

molting  of,  72 

Cryptobranchus  allegheniensis,  125,  126 
Ctenophora,  16 
Culex,  6,  83,  86,  87,  89 
Cultch  for  oysters,  47 
Cuttle-bone,  67 
Cuttlefish,  45 
Cyanocitta  cristata,  195 
Cyclophis  aestivus,  167 
Cyclops,  68 

as  host  of  guinea- worm,  38 
Cyclostomata,  characteristics  of,  108-10 
Cyclura  carinata,  152 
Cyprus,  sponges  of,  12 
Cysticerci,  27,  28 

D 

Darwin,  Chas.,  41 
Dasypodidae,  see  Armadillo. 
Dasypus  novemcinctus  texanus,  262 

sexcinctus,  26 
Day  mosquito,  84 
Deer,  264,  268-74 

former  importance  of,  268 

hides  and  horns,  269 

raising  on  waste  lands,  269 
profits  of,  269 

reason  for  domestication,  269 

Virginia,  272 

age  at  maturity,  272 


Deer,  Viriginia,  domestication  of,  272 
food  of,  272 

gestation  period  of,  272 
Delphinus  delphis,  276 
Demodex  folliculorum,  83 
Dengue  fever,  10 

Dentalium,  see  Elephant's  tusk  shell. 
Devil-fish,  65 
Dew  itch,  35 
Diadem  spider,  80 
Diamond-back  terrapin,  139-44 

breeding  habits  of,  143 

bulls,  cows  and  heifers  of,  140 

carapace  of,  140 

counts,  halves  and  quarters,  141 

crawls,  141,  142 

demand  for,  141 

farm,  140-44 

as  food,  139-44 

food  of,  141 

hibernation  of,  139 

incubation  period,  143 

incubator  for,  143 

intelligence,  144 

propagation  of,  140-44 

size  and  value,  139,  143 

stew,  cost  of,  141 

substitutes  for,  141 
Diatomes,  10 
Dick,  J.  F.,  157 
Didelphis  virginiana,  207 
Digger    ground    squirrel,    see    Ground 

squirrel. 

Diphtheria  and  flies,  92 
Dipnoans,  113 
Dirt-eating  habit,  34 
Distoma,  29 
Distomiasis,  29 
Ditmars,  R.  L.,  154 
Dog  as  rat-killer,  243-44 

family,  212 
Dolphins,  274,  276-77 
Domestic  animals  as  rat  destroyers, .  243 
Dracunculus,  see  Guinea-worm,  38 
Dragon-flies  as  mosquito  destroyers,  88, 
106 


INDEX 


299 


Dredge  for  oysters,  50-52 
Dromedary  or  one-humped  camel,  266 
Dry  grain  formula  for  rodent  poison,  249 
Dryobates    villosus,    see   Hairy   wood- 
pecker. 
Duckbill,  206 
Dugong,  see  Sirenia. 
Dum-dum  fever,  10 
Dynamite,  10 
Dysentery  and  flies,  92 


Earthworm,  40 

abundance,  41 

castings,  40 

damage  done  to  plants,  41 

as  disease  carriers,  41 

distribution,  40 

food,  41 

as  food,  41 

poisoning  of,  41 

South  African  and  Australian  forms, 
40 

value  to  soil,  41 
Echidna,  206 
Echinodermata,  20 
Echinoidea,  20,  24 
Edentata,  260-62 

families  of,  260-66 
Edible  birds'  nests,  see  Birds'  nests,  185 

snails,  see  Snails. 
Eel  worm,  human,  31 

cure,  32 

life-history,  32 

infection,  32 

Egg-laying  mammals,  206 
Elapine  snakes,  153 
Elaps  fulvius,  153,  154 
Elasmobranchii,  108,  113 
Elephant,  capture,  265 

as  beast  of  burden,  265 

as  food,  266 

Indian,  265 

intelligence,  265 

size,  265 


Elephant,  species,  265 

tusks,  265-66 

use  in  Orient,  265 
Elephant's  tusk  shell,  66 
Elephantiasis,  38 
Elk,  270-72 

adaptation  to  domestication,  271 

castration,  272 

cost  of  breeders,  272 

danger  from  bucks,  272 

feed  for,  272 

fence,  272 

former  range,  270 

-hide  clothes,  269 

-horn,  269 

use  and  value  of,  269 

polygamous  habits,  271 

rate  of  increase,  271 

weight,  272 

Embalming  of  rats  by  poison,  241 
Encouragement  of  birds,  198-204 
Entameba  buccalis,  2 

coli,  i,  2 

dysenteriae,  2 

histolytica,  2 
Enteropneusta,  107 
Entire  skins  of  alligators,  172 
Entomology,  83 
Entomostraca,  69 

Epidermal  structures  of  mammals,  205 
Epsom  salts,  36 
Eptesicus  fuscus,  211 
Ermine  skins,  213 
Eutania,  see  Garter  snakes,  162 
Eutheria,  206 
Even-toed  ungulates,  see  Artiodactyla. 


Falco,  192 

peregrinus  anatum,  192 
Fangs  of  pit  vipers,  154,  155 

shedding  of,  155 

Fasciola  (Distomum)  hepatica,  29 
Fat  tapeworm,  27,  28 
Feather  stars,  22,  25 
Felidae,  212 


3oo 


INDEX 


Felt,  E.  P.,  83 
Fertilizer  from  fish,  1 13 
Fiber  zibethicus,  220,  222 
Field  mice,  246-51 

clean  cultivation  as  a  preventative, 
250 

destruction  of,  249-51 
of  enemies  of,  250-51 

poisoning  of,  249-50 

skulls  from  owl  pellets,  250 

trapping,  249 
Filaria,  38 

mode  of  infection,  38 
Filth  fly,  94 
Finback  whale,  278-79 
Findlay,  Carlos  J.,  9 
Fire-hunting  for  alligators,  172-74 
Fish,  cans,  121 

culture,  118-22 

begun  in  the  United  States,  118 
for  family  use,  122 
first  practised,  118 
primary  object  of,  120 

eggs,  artificial  fertilization  of,  120 
transportation  of,  122 

fry,  feeding  of,  121 
transportation  of,  121 

glue,  113 

hatcheries  of  various  states,  120 

hatching  trays,  120,  121 

importance  as  food,  113 

milt,  120 

as  mosquito  destroyers,  88 

poisonous  forms,  113-14 
Fisher,  A.  K.,  191,  192,  251 
Fissipedia  or  carnivora  vera,  212 

families  of,  212 
Flagella  of  sponge,  1 1 
Flakes  for  drying  codfish,  116 
Flat-horned  deer,  269-70 
Flatworms,  26,  27,  28 
Fleas,  methods  of  control,  102 
Flint,  3 

sponge  deposits,  14 
Florida  sponges,  12 

value  of,  14 


Flukes,  26 

sheep,  life-history,  29,  30 

Fly,  as  bacteria  carrier,  93 
control,  94-96 
as  disease  carrier,  92 
favorite  breeding  places,  9 
life-history,  94 
paper,  traps,  etc.,  95-6 
rate  of  increase,  94 
specks,  danger  of,  92 
screens  and  moths,  102 

Flying  ants,  98 
foxes,  210 

Fly's  wing,  hairs  of,  93 

Follicle  mite,  82,  83 

Foot  itch,  35 

Foraminifera,  3,  10 

Forbush,  E.  H.,  197 

Fox,  diseases,  217 

escape  from  pens,  219 
farming  centres,  218 
farms,  value  of,  217 
and  field  mice,  251 
food  of,  219 
gestation  period,  219 
and  ground  squirrels,  254 
kennel,  218,  219 
method  of  killing,  219 
number  in  litter,  219 
pen,  218 

fence  of,  218 
poachers,  220 
raising  of,  214,  216 
ranch  location,  218 

plan,  217 
red,  skin  of,  213 
sexual  maturity,  219 
time  of  killing,  219 

Fresh  water  mussel,  44 

Frog,  age  at  maturity,  132 
artificial  propagation,  130 
centres  for  collection,  129 
eggs,  130 
enemies,  130 
extermination,  130 
flesh,  129 


INDEX 


301 


Frog,  food,  131 
green,  129,  131 
leopard,  129 
marsh,  129 

metamorphosis,  123,  124,  131 
mode  of  collection,  130 
numbers  raised,  131 
pickerel,  129 

preparation  of,  for  food,  128 
shad,  129 
spring,  129,  131 
tiger,  129 
western,  128,  129 
Fumigation  of  houses,  241 

of  ships,  242 
Funston  Bros.,  213 
Fur-bearing  animals,  212 

domestication  of,  214 
-farming,  214 

reasons  for,  214 
Fur-seal,  breeding  season,  224 

controversy  with  England,  226 

convention,  226 

death  of  pups,  224 

diminution  of,  226 

home,  224 

importance,  223 

methods  of  killing,  224 

migration,  224 

natural  history,  224-26 

sales,  226 

skin,  treatment  of,  227 

value  of,  227 

trade,  history  and  value  of,  213 
Furs,  American,  213 
misnomers,  221 


Game  animals,  264 
Gadus  morrhua,  see  Cod. 
Gases  as  rat  destroyers,  241 
Gastropoda,  45,  60 
Gavials,  136 
Geckos,  136 
Gemmules  of  sponge,  1 2 


Geomyideae,  228 

Geomys  bursarius,  see  Pocket  gopher. 
Georgahan,  Dr.,  114 
Giant  clams,  59 

Gila  monster,  effects  of  bite,  150 
fangs,  150 

habits,  150 
Gill  bars,  see  Visceral  bars. 

clefts,  107 
Giraffe,  264 
Glires,  227 
Globigerina,  3 

ooze,  3 

Glossina  palpalis,  3 
Gnawing  animals,  227 
Goat,  264 

skin,  221 

Golden  eagle  and  ground  squirrel,  254 
Goose  barnacles,  69 
Gorilla  gorilla,  262 

habits  and  size,  262-63 
Grasshoppers  as  food,  103 
Grassi,  G.  B.,  7 
Grass  snake,  167 
Great  anteater  of  Brazil,  261 
Greece,  sponges  of,  12 
Green  Harbor  whaling  station,  280 
Greenland  whale,  276-77 
Green  turtle,  137-39 

breeding  habits,  137-39 

centers  and  value  of  industry,  137 

eggs  as  food,  139 

as  food,  137-39 

oil,  137 

poisonous  at  times,  137 

propagation  of,  139 

size  and  distribution,  137 
Grenfell,  Dr.  W.,  274 
Ground  itch,  35 
Ground  squirrels  and  corn,  254 

cost  of  poisoning,  253 

as  carriers  of  plague,  252 

danger  as  food,  259 

destructiveness,  252-54 

food,  252 

habits,  252 


302 


INDEX 


Ground  and  irrigation  canals,  252 

killed  with  poisoned  barley,  253 

loss  by,  251 

means  of  destruction,  252-54 

mound  of,  252 

natural  enemies,  254 

poison  for,  253 

rate  of  increase,  253 

shooting,  254 
Guano  of  bats,  187 

from  birds,  186-87 

from  fish,  187 

from  whales,  281 
Guinea  pigs  as  food,  260 
Guinea- worm,  38 

cure,  38 

life-history,  38 

mode  of  infection,  38 
Giinther,  A.  C.  L.,  110-12 
Gymnoglyphs  calif ornianus,  189 
Gymnophiona,  see  Apoda. 
Gyrfalcon,  192 


II 


Haddock,  116 

Hagfish,  108-10 

Haliotis,  see  Abalone. 

Hard-shell  clam,  see  Little-neck  clam. 

Harlequin  snake,  153-54 

Hartshorn  or  ammonia,  269 

Harvest  mites,  82 

Hatteria,  136 

Havana,  yellow  fever  at,  9 

Hawk,  Cooper's,  192-93 

duck,  192 

hen  or  chicken,  192 

red-shouldered,  192 

red-tailed,  192 

stomach  contents  of,  193 

sharp-shinned,  192 
Hawks  and  owls,  protection  of,  244 

considered  injurious  to  man,  192 

as  destroyers  of  birds,  198 

as    destroyers    of    rodent    pests, 
191-92 


Hawksbill  turtle,  see  Turtle. 

Hedgehog,  210 

Helix,  58 

Hellbender,  125-26 

Helmet  shell,  see  Cameo  shell. 

Heloderma  horridum,  150 

suspectum,  150 
Henshaw,  Saml.,  206 
Herrick,  F.  H.,  72 
Herring,  annual  catch,  144 

sea,  habits  of,  115 

value  of,  114 
Heterodon,  170 
Heteropoda,  see  Tarantula. 
Hexapoda,  70 
Hippopotami,  264 

as  food,  268 
Hirudinea,  40 

Hirudo  medicinalis,  see  Medicinal  leech. 
Holothuroidea,  21,  24,  25 
Homarus     americanus,     see     Lobster, 
American. 

gammarus,  71 
Honey,  adulteration,  104 

annual  production  of,  103 

bees,  103,  104 

as  food  and  medicine,  104 

from  mountain  laurel,  104 
Hoofed  animals,  see  Ungulata. 
Hookworm,  33,  34 

in  Bilibid  Prison,  36 

care,  36 

discovery  of  mode  of  infection,  35 

distribution,  33 

effects,  36 

eggs,  35 

first  reported,  33 

infection,  35 

length  of  life,  34 

life-history,  35,  36 

number  of,  34 

in  Porto  Rico,  33 

prevalence,  33 

in  United  States,  33 
Hornaday,  W.  T.,  212 
Horns  of  deer,  shedding  of,  269 


INDEX 


303 


Horse,  264 

as  food,  265 

Horse-shoe  crab,  see  King  crab. 
House  centipede,  79 
House-fly,  89,  96 

eggs,  93 

how  recognized,  92 

leg,  92 

and  roaches,  89-90 

wing,  91 
House-mouse,  244 

in  Australia,  245 

extermination  of,  245 

habits,  245 

incredible  numbers  caught,  245 

method  of  capture  in  Australian 

wheat  stacks,  245 
Hudson  Bay  Company,  213 
Hudson  Bay  seal,  220,  222 
Human  eel  worm,  31 
Hump-back  whale,  278 
Hydatids,  29 
Hydrocyanic  acid  and  bedbugs,  102 

for  destruction  of  rats,  241 
Hydrophobia,  2 
Hydrozoa,  15,  1 6 
Hylidae,  127 
Hyracoidea,  264 
Hystrix  cristata,  see  Porcupine. 


Ichneumon  fly  and  host,  105,  106 
Iguana,  136,  150,  152-53 

capture,  153 
India,  deaths  from  crocodiles,  176 

from  snakes,  156 
Infusoria,  10 
Infusorial  earth,  10 
Insecta,  69,  106 

annual  losses  from,  83 

characteristics,  70 

as  food,  103 

intelligence,  70 

number,  60-70 

predacious  and  parasitic  on  other 
insects,  106 


Insecta,  in  relation  to  agriculture,  83 

species,  83 
Insectivora,  208 

Insect  larvae,  destruction  of,  by  birds,  226 
International  fur-seal  treaty  of  1911,  226 
Iodine  and  snake  bites,  157 
Isinglass,  113 

Isle  of  Hope  terrapin  farm,  140-44 
Itch  mite,  82,  83 
Ivory  trade,  266 


Jackfish,  113 
Jack-rabbit,  254 

hunting  of,  255 
Jackson,  Dr.,  272 
Jays,  195 
Jones,  J.  W.,  214 
Jordan,  D.  S.,  no 
Julus,  79 
Junco,  196 


Kala-azar  fever,  10 
Kangaroo,  206-08 

food,  207 

leather,  208 

number  of  species,  207 

size,  208 

Karakul  sheep,  214,  215 
Kellogg,  V.  L.,  79-80 
Kerosene  and  mosquitoes,  88 
Key  West  sponges,  13 
Kid  skin,  222 
Kilborn,  4 

Killer  whale,  habits  and  size,  278 
Killing  ground  of  seals,  224 
King  crab,  82,  184 

classification,  82 

for  fertilizer,  82 

habitat  and  size,  82 
Kingfish,  113 
Kirkland,  H.  A.,  134 
Kitchen  middens,  45 


304 


INDEX 


Kiwi,  179,  180 
Robert,  80 

Kraals  for  sponges,  13 
Krimmer,  215 


Lacertilia,  characteristics,  136;  see  Liz- 
ards, 148-53 
Ladybird  beetles,  106 
Lamb  skins,  215 
Lamellibranchiata,  44,  63 
Lampern,  see  Lamprey. 
Lamprey,  108,  109 

as  food,  1 08 

parasitic  habits,  108,  no 
Lancets,  107 
Lancisi,  6 

Lantz,  D.  E.,  229,  244,  269,  272-73 
Laomedia,  15 
La  Paz  pearl  fishery,  62 
Lapland     reindeer,     introduction     into 

Alaska,  272 

Lasiums  noveboracensis,  211 
Latra  canadensis,  219 
Latrodectus  mactans,  80,  81 
Laveran,  6 

Laws  relating  to  sale  of  venison,  271 
Lazear,  Dr.  Jesse  W.,  9 
Lazy  germ,  34 
Leech,  adaptation  to  environment,  42 

digestive  system,  42 

as  food,  43 

Lepas,  see  Goose  barnacle. 
Leopard  skin,  222 
Leporidae,  228 
Lepus,  see  Rabbit. 
Lime-and-sulphur    mixture    to    protect 

trees  against  rodents,  257 
Limulus,  see  King  crab. 
Lion  skin,  222 
Liopeltis  vernalis,  167 
Little  brown  bat,  210,  221 
Little-neck  clam,  54,  56 

collection  of,  55 

culture,  56 


Little-neck  clam,  depletion  of  beds,  55 

distribution  and  habitat,  54,  55 

enemies,  55, 

value  of,  55 
Liver  fluke,  26,  29 
Livestock  destruction,  212 
Lizards,  beaded,  150 

confused    with    salamanders,    123, 
148 

fence,  151 

as  food,  150,  152-5,3 

food  of,  150 

poisonous,  148-50 

stomach  contents,  150 
Llama,  as  beast  of  burden,  267 

domestication  of,  267 
Lobster,  69-74 

activities  and  migration,  72 

age,  72 

American,  71-74 

annual  catch,  71 

berried,  72 

protection  of,  74 

capture,  72,  73 

culture,  73,  74 

depletion  of  supply,  7 1 

feeding  habits,  72 

grounds,  71 

hatcheries,  74 

molting,  72 

number  of  eggs,  72 

pots,  72,  73 

rate  of  breeding,  72 

shipment,  73 

size,  71 

spearing  by  Indians,  72 

spiny,  74 

transplanting  to  Pacific  coast,  73 

use  by  Pilgrims,  71 

value,  71 

Locusts  and  wild  honey,  103 
Loggerhead  turtle,  139 
Loligo  pealii,  see  Squid. 
Long-neck  clam,  collection,  54 

habitat,  54 

siphons,  54 


INDEX 


305 


Looss,  A.  C.,  35 

experiments  of,  35 
Lophortyx  californicus,  188 
Loxodonta  africanus,  266,  see  Elephant. 
Lumbricus,  see  Earthworm,  40 
Lung-fishes,  113 
Lynx  skins,  213 

M 

Macaque,  263 
Macropus  robustus,  208 
Maggots  of  flies,  94 

trap,  95,  96 

Malacoclemmys  palustris,  139 
Malacostraca,  69 
Malaria,  6 

mosquito,  see  Anopheles. 

transmission,  6,  7 
Mammalia,  108,  205 

blood,  206 

characteristics,  205,  206 

classification,  206 

flesh-eating,  211 

known  species,  206 

migration,  205 

ovum,  205 

placenta,  205 

uterus,  205 

variation  in  size,  205 
Man,  262 
Manatee,  fine  for  killing,  274 

in  Florida,  274 
Manatus,  see  Sirenia. 
Man-eating  sharks,  no 

-killing  ostrich,  182 
Mangrove  oysters,  5 1 
Manson,  Patric,  6 
Manure  and  flies,  95 

care  of,  95,  96 

Marine  Hospital  Service,  34 
Marsh  hare,  221,  260 
Marsh  Island  bird  preserve,  203 
Marsupialia,  206 

characteristics,  206 
Marsupium,  206 
20 


Marten  family,  212 

Martin  house,  201 

Mastigophora,  i,  3 

McLean  migratory  bird  law,  178,  198, 

200 
Meadow  mice,  246-51 

damage  by,  247-48 

habits,  246-48 

rate  of  increase,  247 
Meat  packing,  265 

production,  264-65 
Medicinal  leech,  41,  42 

use  in  medicine,  42,  43 
Mediterranean  sponges,  12 
Medusa,  16 
Megaptera     nodosa,     see     Hump-back 

whale. 

Megascops  asio,  192 
Menhaden,  113 
Mephitis,  221 
Merriam,  C.  H.,  193 
Mesozoic  reptiles,  135 
Metridium,  marginatum,  17 
Mice,  205,  244-51 
Mice  and  rats,  228 

key  to  species,  229 
Microtus,  see  Meadow  mice. 
Milk  teeth,  205 
Millipedes,  69,  79 
Mink,  220,  222 

skins,  213,  221 
Miricidium,  29 
Moccasin,  see  Snake. 
Mock  ermine  skin,  222 

pearls,  113 
Moles,  205,  208-10 
Mollusca,  44 

classification,  44,  45 
Monkeys,  262,  263 
Monodon  monoceras,  see  Narwhale. 
Monotremata,  205,  206 

characteristics,  206 

derivation  of  name,  206 
Moose,  260-70 

as  beast  of  burden,  270 

endurance  and  speed,  270 


306 


INDEX 


Mosquito,  artificial  transportation,  87 

captive,  84 

in  cisterns,  88 

control,  82,  89 

destruction  of,  by  dragon  flies  and 
fish,  88 

and  disease,  83 

larvae,  85-89 

length  of  flight,  86 
of  life,  86 

life-history,  84,  85 

number  of  species,  83 

pupae,  86,  89 
Moth  balls,  101 
Mother-of-pearl,  60 
Mountain  lions,  212 
Mouse  bait,  245 

traps,  245 

Mowbray,  L.  L.,  113,  114 
Mud  puppy,  125-26 
Murex,  60 
Muridae,  227,  228 
Murre's  eggs,  184 
Musca  domestica,  see  House-fly. 
Muskrat,  222 

age  at  sexual  maturity,  221 

collection,  221 

distribution,  220 

as  food,  260 

importance,  220 

musk  of,  221 

number  of  skins  sold,  220 

raising,  214 

rate  of  breeding,  221 

skins,  213,  221 

Mus  musculus,  see  House  mouse. 
Mussel,  44 
Mustelidae,  212 
Mustelus,  in 

Mya  arenaria,  see  Long-neck  clam. 
Myotis  lucifugus,  210,  211 
Myriapoda,  69,  78 

characteristics,  69 
Myrmecophaga  jubata,  261 
Myrmecophidae,  see  Anteater. 
Mystacoceti,  see  Whalebone  whales. 


Mytilus  edulis,  see  Salt-water  mussel. 
Myxine,  108-10 

N 

Naphtha  for  moths,  102 
Naphthalene  for  moths,  101 
Narwhale,  tusk,  2^3,  251 
Nautili,  45 

Necator  americanus,  33,  34 
Necturus  maculatus,  125,  126 
Negri,  2 

bodies,  8 
Negroes  and  hookworm,  36 

immunity  to,  36 
Nemathelminthes,  31 
Nelson,  E.  W.,  vi,  213 
Neornithes,  178 
Neurocytes  hydrophobiae,  2,  8 
Neuroptera,  96 

New  York  Fur  Sales  Corporation,  213 
Noddy,  184 
Northern  raven,  195 
Norway  rat,  see  Brown  rat. 
Norwegian  whalers  first  visit  America, 

279 

Notochord,  107 
Nummulites,  3 
Nummulitic  limestone,  3 


Obelia,  15 

Octopus,  see  Devil  fish. 

Odd-toed  ungulates,  see  Perissodactyla. 

Odocoileus    (Cariacus)    virginiana,    see 

Deer. 

Odontoceti,  see  Toothed  whales. 
Ogliole,  17 

One-humped  camel  or  dromedary,  266 
Onychophora,  69,  78 
Ophibolus  doliatus  triangulus,  167 

getulus,  169 
Ophidia,  see  Snakes. 

characteristics,  136 
Ophiuroidea,  22,  24,  25 
Opisthoglyph  snakes,  153 


INDEX 


307 


Opossum,  206,  207 

and  field  mice,  251 

skins,  213,  221 
Orang-utan,  262 
Orca  orca,  see  Killer  whale. 
Oriental  dysentery,  2 
Ornithorhynchus,  206 
Osculum  of  sponge,  1 1 
Osier,  Sir  Wm.,  27 
Ostrich,  eggs,  182-83 

farms,  184 

farming  methods,  184 

food,  182 

as  food,  184 

habitat  and  size,  180,  181 

habits,  182 

method  of  plucking,  183 

mode  of  capture,  182 

plumage,  183 

profits  of  raising,  183 

size  and  food  of  young,  184 

value  of  farms,  183 
of  pair,  183 
of  plumes,  184 
Otter,  172,  219-20 
Owl,  barn,  192 

as  destroyer  of  rodent  pests,  191- 
92 

and  field  mice,  250-51 

great  horned,  food  of,  192 

screech,  192 
Ox  warble,  91 
Oyster,  absence  of  diseases,  50 

abundance,  45 

age  at  maturity,  47 

anatomy,  46 

artificial  fertilization,  47 

beds,  48 

collection,  50 

conservation,  47 

culture,  47 

depths  for  collecting,  51 

and  disease  germs,  47,  51,  52 

dredge,  50-52 

drills,  50 

effect  of  floating,  53 


Oyster,  enemies,  50 
European,  47 
floated,  53 
food  of,  47 
legislation,  50-52 
life-history,  47 
number  of  eggs,  47 
and  sewage  contamination,  52 
shipment,  52,  53 
survey  of  beds,  48 
tongs,  50,  51 
on  trees,  51 
and  typhoid  fever,  52 
various  beds,  45 
virginiana,  45 
wild  crop,  45 
young,  49 


Palaemon,  78 

Palinurus  interruptus,  74 

vulgaris,  74,  see  Spiny  lobster. 
Pallets  of  shipworm,  66 
Panama  Canal,  health  of,  9,  10 
Paramecium,  10 
Passenger    pigeon,     extermination    of, 

184-85 
Pearl,  60 

buttons,  62,  63 

divers,  62 

in  edible  oysters,  61 

fisheries,  61,  62 

formation  of,  60-6 1 

mussels,  62 

oysters,  61 

value,  6 1 
Pecten  irradians,  see  Scallop 

tenuicostata,  see  Scallop. 
Pelagic  sealing,  224 

prohibited,  226 

why  so  destructive,  226 
Pelecypoda,  see  Lamellibranchiata 
Peludo,  261 
Penguins,  180 
Peripatus,  69-70 
Periphylla  hyacinthiana,  16 


308 


INDEX 


Perissodactyla,  264 

Peris  tome,  21 

Permanent  teeth,  205 

Pernicious  fever,  6 

Persian  lamb,  215 

Petroleum,  discovery,  280 

Petromyzon,  108-10,  see  Lamprey. 

Phosphorus  as  rat  poison,  241 

Physeter  macrocephalus,  277  • 

Pigs,  264 

Pilchard,  116 

Pine  mouse,  209,  246-51 

burrows  distinguished  from  those  of 
mole,  248 

destructiveness,  248-49 

distribution  and  habitat,  248 

rate  of  increase,  249 
Pinnipedia,  see  Seals,  212,  223 
Pin  worm,  39 
Pisces,  107-22 

classification,  108 
Pithecus,  263 
Pituophis,  167-68 

sayi,  1 68 
Pit  viper,  154 

effect  of  poison,  155 

the  pit,  154 

skull,  155 

Pitymys,  see  Pine  mouse. 
Placuna  placenta,  see  Window  shell. 
Planaria,  26 

Plant  lice  and  ladybird  beetles,  106 
Plasmodium,  4 

cyst,  7 

spores,  6 

sporulation,  7 
Platyhelminthes,  26 
Platypus,  206 
Pocket  gopher,  damage  by,  258 

destruction  of,  258-59 

distribution,  258 

traps,  259 

tunnels,  258 
Poison  for  ground  squirrels,  253 

protection  of  birds  from,  250 

for  rats,  241 


Poisonous  fish,  113,  114 
Poland,  P.  R.  &  Son,  226 
Polyp,  1 6 
Pony  skin,  222 
Poor  whites,  33,  34 
Porcelain  shells,  see  Cowries. 
Porcupine,  205,  259 

as  food,  260 
Pores  of  sponge,  1 1 
Porifera,  n,  see  Sponge. 
Pork  tapeworm,  27,  28 
Porpoises,  277 
Potassium     permanganate     for     snake 

bites,  157 

Potato  formula  for  rodent  pests,  249 
Power  and  hand  looms,  104 
Prawns,  78 

Precious  coral,  see  Coral. 
Predatory  animals,  destruction  of,  212 

mammals,  value  of  skins,  212 
Pribilof  Islands,  224 
Primates  as  food,  263 

characteristics,  262 
Prince  Edward  Island,  218 
Proboscidea,  264 
Procyonidae,  212 
Proglottid  of  tapeworm,  27 
Progne  subis,  201 ,  see  Purple  martin. 
Prototheria,  206 
Protozoa,  i 

Psoroptes  communis,  83 
Ptomain  poisoning  from  fish,  114 
Pup  seals,  224 
Puppy  skins,  222 
Purple  martin,  value  of,  201 
Pusher  for  scallops,  56 
Putorius  vison,  220 


Quadrumana,  263 

Quahog,  see  Little-neck  clam. 

(Quahang),  meaning  of  word,  55 
Quail,  California,  188 
Quartan  fever,  6 
Quartz,  3 


INDEX 


309 


Quinnat  or  king  salmon,  size  of,  116 
Quiscalus,  195 


R 


Rabies,  2 

Rabbit,  damage  by,  254-55 

food,  254 

means  of  destruction,  255 

poisoning  of,  257 

protection  of,  255 
of  gardens  from,  257 
of  trees  from,  257 

rate  of  increase,  254 

skin,  222 

species  in  North  America,  254 

traps,  256-57 

value  as  food,  255 
Raccoon  family,  212 

and  field  mice,  251 

skin,  213 
Radiata,  20 
Radiolaria,  3 
Radiolarian  ooze,  3 
Rana  catesbiana,  128 

clamata,  129,  131 

palustris,  129 

virescens,  129 
Rangifer  arcticus,  272,  273 

caribou,  272 

tarandus,  272 
Ranidae,  127 

breeding  habits,  130 

as  food,  127-28 

number  of  species,  127 
Rat,  age  at  sexual  maturity,  228 

albino,  230 

bait,  238-39 

and  bubonic  plague,  228 

campaigns,  243-44 

characteristics  and  distribution,  229 

cleanliness  as  prevention,  244 

clubs,  244 

damage  by,  228 

destruction  of  harbors,  244 
cooperation  in,  243-44 


Rat,  and  disease,  228 

early  threshing  of  grain,  244 

food  of,  230 

habits,  230 

introduction     into     Europe     and 

America,  230 
killing  in  burrows,  243 

by  fumes,  241-43 
Lantz's  measures  for  rat  warfare, 

244 
methods  of  protecting  food  from, 

234 
and  mice,  228 

as  destroyers  of  birds,  198 

as  food,  260 

key  to  species  of,  229 
migration,  231 
in  mills,  231 
natural  enemies,  243 
nocturnal  habits,  231 
numbers  of,  231 
original  home,  230 
poisons,  238,  240-41 

protection  of  domestic    animals 

from,  241 
population,  231 
posters,  232-33 
prolificness,  232 
proofing  barns  and  buildings,  234- 

35 
with  concrete  and  wire  netting, 

235 

corn  cribs,  235-37 

by  elevation,  235 

protection  of  natural  enemies,  244 
rat-proof  garbage  cans,  234 
sewer  rat,  244 
shields,  242 

systematic  destruction  of,  244 
three  kinds,  228 
traps,  238-39 

barrel,  240 

guillotine,  238-39 

snap,  238 

wire,  239 
use  of  rat-proof  containers,  244 


3io 


INDEX 


Rat,  viruses,  243 

white,  230 
Ratitae,  178 

Rattler,  timber  and  mouse,  156 
Rattlesnake,  deaths  from,  156 

head  of,  154 

oil,  170,  see  Snake. 
Rattus  norvegicus,  see  Brown  rat. 

rattus  alexandrinus,  see  Roof  rat 

rattus,  see  Black  rat. 
Ray,  iio-i2 

electric,  112 

sting,  in 
Red  ants,  in  tropics,  103 

control,  103 
Red  bat,  211 
Red  fox  skins,  213,  216 
Red  rockfish,  113 

Red  squirrels  as  destroyers  of  birds,  198 
Redia,  29 

Reed,  Dr.  Walter,  9 
Reindeer  and  Eskimos,  273 

European,  272 

groups  of,  272 

herds,  272 

in  Labrador,  274 

numbers  in  Alaska,  273 
Reptilia,  108,  135-76 

characteristics,  135 

classification,  135 

Mesozoic,  135 

number  of  living  species,  135 

orders  of  living,  135-36 

relation  to  birds,  135 
Rheas,  180 
Rhinoceros,  264 

as  food,  268 
Rhizopoda,  123 
Rhynchocephalia,  126 
Ricketts,  H.  T.,  157 
Roaches,  methods  of  control,  102 
Rock  crab,  77 

lobster,  see  Lobster,  spiny. 
Rockefeller  Hookworm  Commission,  36 
Rodentia,  227 

characteristics,  227 


Rodentia,  families,  227-28 

as  food,  259 

most  destructive  group,  228 

number  of  species,  227 

teeth,  227 
Roof  rat,  229 
Ross,  Ronald,  6 
Rotifers,  26 
Rough    skeleton    prepared    by    carrion 

crows,  189 

Round-horn  deer,  270 
Round  worms,  31 
Rumen,  264 
Ruminants,  264 


Sable  mink  skin,  221 

Sacred    clam    shells,    formation   of,    61 

Sage,  Mrs.  Russell,  203 

Salamanders,  126 

Salientia,  124-26 

Salmonidea,  116 

Salmon,  breeding  habits,  117 

canneries,  113 

derivation  of  name,  116 

value  of  industry,  117 
Salt-water  mussel,  57,  58 
Sand  and  oysters,  50 
Sarcoptes  scapici,  83 
Sardine,  annual  output  of  France,  116 

in  California  and  Maine,  116 

origin  of  name,  116 
Sauropsida,  135 

Scale  insects  and  ladybird  beetles,  106 
Scallop,  56 

collection,  56 

distribution,  56 

perishability,  56 

shells  for  cultch,  48 

size  and  value,  56 
Scalopus  aquaticus,  209,  see  Mole. 
Scaphopoda,  45,  66,  67 
Sceloporus  spinosus,  151 

undulatus,  151 
Sciuridae,  228 


INDEX 


311 


Scolex  of  tapeworm,  27 
Scolopendra,  78 
Scorpions,  148 

sting,  82 

Scutigera  forceps,  79 
Scyphozoa,  16 
Sea  anemone,  16,  17 
Sea  cows,  274-75 

characteristics  and  habits,  274 
Sea  cucumber,  21-24 
Sea  eggs,  24 
Sea  lilies,  22,  25 
Sea  lion,  212 

Sea  mussel,  see  Salt-water  mussel. 
Sea  squirts,  see  Tunicates. 
Sea  urchin,  20,  22-24 

annual  value,  24 
Sea  walnuts,  16 
Sea  weeds  and  oysters,  50 
Seal  cony  skin,  222 

harem,  224 

rookeries,  224 

skins,  222 

price  of,  227 
Seals,  205,  212,  223 
Seed  oysters,  48 
Segmented  worms,  40 
Sepia,  67 

Serpent  stars,  22-25 
Sewer  rat,  see  Brown  rat. 
Shad,  introduction  into  California,  115 

breeding  habits,  115 

eggs  produced,  115 

fry  hatched  by  Bureau  of  Fisheries, 

US 

Shagreen  from  sharks,  113 
Shark,  dogfish,  damage  by,  in 

basking,  112-13 

oil,  112 
Sharks,  no,  in 

damage  to  fish  and  fisheries,  no 

deaths  from,  no 

great  white,  no 

man-eating,  no 

and  rays  as  food,  112 

for  production  of  gelatine,  112 


Sharks,  size,  no 

used  for  fertilizer,  112 
Sheep,  264 

Karakul,  214-15 
Sheep-scab,  83 

mite,  82 

Shell-fish  as  food  of  prehistoric  man,  45 
Ship  of  desert,  267 
Shipworm,  direction  of  burrow,  64 

food  and  rate  of  growth,  64 

life-history,  64 

method  of  boring,  66 

prevention  of  damage,  66 

size  and  fecundity,  64 

valve,  64 

Short-tailed  mice,  see  Field  mice. 
Shrews,  205,  208,  209 
Shrimps,  78 
Silk,  annual  production  of,  in  Japan,  104 

industry  centres,  104 

origin  of  industry,  104 

production  and  cheap  labor,  106 
Silkworm,  cocoon  of,  104,  105 

habits,  104,  105 

introduction     into     Europe     and 
America,  104 

number  of  species,  104 
Silver  foxes,  number  in  captivity,  220 

value  of  skins,  216 
Sirenia,  274 

as  food,  274 

skins  for  leather,  2  74 
Sistrurus,  161-62 

miliaris,  162 
Skins,  market  prices,  214 

misnamed,  222 

preparation  of,  214 
Skunk,  220-22 

and  field  mice,  251 

protection  of,  223 

raising,  214 

skins,  213,  222 
Sleeping  sickness,  3,  4 

victim  of,  4 
Sloths,  260-61 

habits,  262 


3I2 


INDEX 


Smallpox  and  flies,  92 
Smith,  Theobald,  4 
Snail,  farms,  58 
gardens,  58 
pens,  58 

Snaileries,  see  Snail  farms. 
Snails,  edible,  breeding  habits,  58 
culture,  in  U.  S.,  58 
methods  of  cooking,  58 
number  used,  58 
season,  58 
and  slugs,  45 
Snake,  banded  or  yellow  chicken  snake, 

167 

banded  water,  confused  with  moc- 
casin, 164 

bite  and  alcohol,  157 
protection  against,  157 
treatment  of,  156-57 
black  coluber,  166 

racer,  166 

blacksnake,  165,  166 
blue  racer,  166 
brown  or  ground,  164 

water,  164 
bull,  167-68 
coluber,  166 
common  king,  chain  or  thunder, 

167,  169 
water,  163,  164 
copperhead,  153,  154,  156,  159,  160, 

162 

effect  of  bite,  161 
cottonmouth  moccasin,  159 
diamond  rattler,  161,  162 
Emory's  coluber,  166 
four-banded  coluber,  167 
fox  or  red-headed  coluber,  166 
garter,  162-64 

gopher,  indigo  or  rat,  164,  166 
green,  167 

highland  moccasin,  see  Copperhead, 
hog-nosed,  170 
king,  167,  169 
milk  or  house,  167 
moccasin,  153-54,  156,  158 


Snake,  moccasins,  so-called,  159 

non-venomous,  162 

pigmy  or  ground  rattler,  162 

pilot,     distinguished    from    black 
racer,  166 

puff  adder  or  blowing  viper,  170 

racers,  164-66 

rat  or  chicken,  166 

rattlers,  size  of,  162 
pigmy  or  ground,  156 
rattle  as  indication  of  age,  162 
shedding,  162 

red,  chicken  or  corn,  166 
coluber,  165 

spotted  adder,  167 
chicken,  166 

striking  distance,  154 

venom,  types  of,  157 

venomous  and  non-venomous,  153 

water  moccasin,  159 

wine,  170 
Snakes,  as  destroyers  of  mice,  251 

as  food,  170 

Snapping  turtle,  see  Turtle. 
Snowshoe  rabbits,  254 
Snyder,  T.  E.,  99 
Soft-shell  clam  rake,  54 

-shelled  clam,  see  Long-necked  clam. 

-shelled  turtle,  144,  see  Turtle. 
Soil  pollution,  36 
Sonora  coral  snake,  153-54 
Sooty  tern,  184 
Soricidae,  209 

South  American  ostriches,  see  Rheas,  180 
South  Georgia  whaling  station,  281 
Spanish-American  War,  typhoid  fever, 

94 
Sparrow,  English  or  house,  damage  by, 

194-95 

time  and  place  of  introduction,  195 
Sparrow,  fox,  196 

tree,  196 

white- throated,  196-. 
Spat  of  oyster,  47 
Sperm  oil,  278-81 

amount  from  single  whale,  281 


INDEX 


Sperm  oil  business  in  1864,  279 

in  1902,  280 
first  use  of,  279 

whale,  size,  277 
Spermaceti,  281 
Sphenodon,  136 
Spicules  of  sponges,  1 2 
Spider,  bite,  80,  82 

black  widow,  79-82 

characteristics  and  distribution,  80 
Spiders,  79 

poisonous,  79 
Spilotes,  164 

corais  couperi,  164 
Spiny  anteater,  206 
Spiny  lobster,  see  Lobster,  spiny. 
Sponge,  cleaning  of,  13 

distribution,  12 

fisheries,  13,  14 

fishing,  12,  13 

industry,  12,  13,  14 

propagation  of,  14 

supply,  14 

varieties,  14 
Sponges,  n,  50 

classification,  12 

colony  of,  n 

damage  to  molluscs  by,  14 

Florida,  14 

fossil,  12 

reproduction,  12 

structure,  n,  12 

value,  13 
Spongin,  12 
Sporocyst,  29 
Sporozoa,  i,  2,  46 
Sporozoites  of  plasmodium,  7 
Spotted  salamander,  126 
Spouting  of  whales,  276 
Squalus,  in 
Squamata,  136 
Squids,  45,  65 
St.  Mark's  Key  sponges,  13 
Stable-fly,  wing,  91 
Starfish,  20,  21 

destructiveness  to  oysters,  50 


Starfish,  removal  from  oyster  beds,  50 
Stegomyia,  8,  9,  83-85 
Stiles,  C.  W.,  34 
Stingarees,  see  Sting-rays. 
Sting-cells,  17 
Sting-rays,  in 
Stomach  of  ruminant,  264 
Stone-lilies,  22,  25 
Stripping  fish,  120 
Strix  pranticola,  192 
Struthio  camelus,  180,  184 
Struthiones,  180 

Strychnine  for  killing  pocket  gophers, 
258 

field  mice,  249-50 

rats,  241 

Sturgeons,  117,  118,  119 
Sulphur-bottom  whale,  277,  282 

dioxid  for  killing  rodents,  241 
Surface,  F.  A.,  137,  150 
Surra,  4,  92 
Swift,  spiny,  151 

Texas,  151 
Swordfish,  capture  of,  117 

size,  117-18 

steaks,  117 

Sylvilagus,  see  Rabbit. 
Syria,  sponges  of,  12 


Tadpole,  food,  131 

metamorphosis,  123-24 
Taenia  saginata,  27,  28 

solium,  27-29 
Talpidae,  209 
Tampa  sponges,  13 
Tangle,  50 
Tapeworm,  26-28 

cure,  27 

eggs,  27 

embryo,  27 

life-history,  27,  28 

regeneration,  27 
Tapir,  264 
Tarantula,  79-81 

bite  of  so-called,  80,  81 


INDEX 


Tatusia,  see  Dasypus. 

Teleost  fishes,  113 

Teredo  navalis,  see  Shipworm. 

Termes,  96 

Termites,  96-100 

in  books,  98 

classification,  96 

damage  to  houses  by,  98 

as  food,  103 

habitat,  TOO 

king,  queen  and  worker,  98 

method  of  control,  99-100 

number  of  species,  96 

size  of  colonies,  98 

swarming,  98 

in  tropics,  98 

use  of  concrete,  99-100 

in  wood,  97 

Terrapene  (Cistudo)  Carolina,  147 
Terrapin,    diamond-back,    139-44,    see 

Diamond-back  terrapin. 
Terrapins,  136 
Tertian  fever,  6 
Tessera  princeps,  16 
Testudinata,  see  Chelonia. 
Tetrapturus,  see  Swordfish. 
Texas  cattle  fever,  82 

fever,  4 

Thalassochelys  caretta,  139 
Threadworms,  31 
Thymol,  36 
Ticks,  82,  83 
Tiger  rockfish,  113 

skin,  222 

Tinea  pellionella,  101 
Toad,  age  at  sexual  maturity,  133 

American,  132-34 

breeding  habits,  133 

causing  warts,  132 

common,  132-34 

eggs,  133 

enemies  of,  134 

as  food,  134 

food  and  feeding  habits,  133 

found  in  rocks,  133 

hibernation,  133 


Toad,  as  insect  destroyers,  133-34 

number  of  insects  eaten,  133 

protection  of,  134 

self-protection,  132 

stomach  contents,  134 

venom,  132 
Tolstoi  rookery,  225 
Tongs  for  oysters,  50,  51 
Tongue  of  snake,  154 
Tooth  shell,  see  Scaphopoda,  45 
Toothed  whales,  274,  276-77 
Torpedo,  see  Electric  ray. 
Tortoise  shell,  148 
Tortoises,  136 
Trapping,  cruelty  of,  214 

wastefulness  of,  214 
Tree  frogs,  127 
Trees  girdled  by  meadow  mice,  247-48 

by  pine  mice,  248-49 
Trematoda,  26,  29 
Trepang,  25 
Trichinella,  infection  of  hog,  37 

life  of  cyst,  37 

life-history,  37 

number  of  cysts  in  body,  37 

(Trichina)  spiralis,  37 
Trichiniasis,  37 

cure,  38 

death-rate,  38 

prevalence,  38 

prevention,  38 
Tridacna,  see  Giant  clams. 
Trionyx,  144 

Tropidonotus  fascia tus,  163,  164 
Trypanosoma,  3 

gambiensis,  3 
Trypanosomiasis,  3,  4 
Tsetse  fly,  3 

Tuberculosis  and  flies,  92 
Tunicata,  107 
Turbellaria,  26,  27 
Turkey  buzzard  as  disease  carrier,  189 

or  vulture,  188,  189 
Turkish  sponges,  12 
Turtle,  common  box,  habits  of,  147 
distribution,  147 


INDEX 


315 


Turtle,  common  snapping,  144 
food  of,  144 
mode  of  capture,  144 
size  and  value,  144,  146 
eggs  as  food,  139 
hawksbill,  148,  149 
characteristics,  148 
removal  and  fusing  of  plates,  148 
loggerhead,  139 
map,  147 
musk,  147 
red-bellied,  147 
soft-shelled,  144,  146 
speckled,  147 
wood,  147 
Turtles,  136 

as  insect  destroyers  and  scavengers, 

148 

mode  of  capture,  147,  148 
Tusks  of  elephants,  size,  266 
Two-humped  camel,  266 
Two-toed  sloth,  260 
Typhoid  fever  and  flies,  92 

epidemics,  94 
Typhoid  fly,  92 

U 

Unarmed  tapeworm,  27,  28 
Ungulata,  263-74 

characteristics,  264 

orders,  263-64 
Unionidae,   for  pearls   or   buttons,    61, 

62,63 

Unio  shell  drilled  for  buttons,  63 
Upper  Jurassic  birds,  178 
Ursidae,  212 
U.  S.  Bureau  of  Fisheries,  see  Bureau  of 

Fisheries. 
U.  S.  Fish  Commission,  118 


Velvet,  horns  in,  271 

Venal  flukes,  29 

Venison,  in  ancient  times,  268 

digestibility,  268 

of  elk,  271 


Venus'  basket,  22 

Venus  mercenaria,  see  Little-neck  clam. 

Vermes,  26 

Vertebrata,  107-285 

classes  of,  108 
Vespertilio  subulatus,  210 
Viperine  snakes,  154 
Virginia  opossum,  207 
Viruses,  rat,  243 
Visceral  bars,  107 

clefts,  see  Gill  clefts. 
Viviparous  mammals,  206 
Voles,  see  Field  mice. 
Vulpes,  216 
Vulture,  California  or  condor,  189 


W 


Wallabies,  207 

Walmsley  trap  for  rabbits,  256 

Walrus,  212 

Wampum,  60 

Wapiti,  see  Elk. 

Water  dog,  see  Mud  puppy. 

Water  flea,  68,  69 

Water -vascular  system,  20 

Weasel,  222 

and  field  mice,  251 
West  India  sponges,  12 
Wet  grain  formula  for  rodent  poison,  249 
Whale,  finback,  278-79 

fisheries,  280 

humpback,  278 

largest,  277 

oil,  278-81 

sperm,  277 

sulphur-bottom,  277 

whalebone,  274,  276-77 

whale,  food  of,  277 
Whalebone,  see  Baleen. 
Whales,  205,  274-85 

characteristics,  habits  and  size,  276- 

77 

as  food,  285 
guano  from,  285 
other  products,  281 


316  INDEX 

Whaling,  business,  profits,  281  Woodpecker,  hairy,  190 

vessels,  279,  281,  283  Wood,  treatment  against  shipworm,  66 

Wharf  rat,  see  Brown  rat.  Woolly-heads,  84 

Whipworm,  39  Wrigglers  of  mosquitoes,  85 
White,  211 

White  ants,  see  Termites.  ^ 

White  heron,  186-87 
White  rabbit  skin,  222 

Wildcats  and  field  mice,  25 1  YeUow  f ever'  8>  9 
Wild  honey,  103  mosquito,  see  Stegomyia. 

oysters,  48  transmission  of,  9 

Window  glass  shell,  59 

cultivation  of,  59  Z 

Wolves,  212  Zamenis,  164 
Woodchuck  as  food,  260  constrictor,  165,  166 

skull  of,  227  Zebra,  264 


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